Import /bin/sh from FreeBSD r281718

59 files changed, 18928 insertions, 0 deletions

diff --git a/external/sh/alias.c b/external/sh/alias.c
new file mode 100644
index 00000000..ddaa4884
--- /dev/null
+++ b/external/sh/alias.c
@@ -0,0 +1,255 @@
+/*-
+ * Copyright (c) 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)alias.c	8.3 (Berkeley) 5/4/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: head/bin/sh/alias.c 263777 2014-03-26 20:43:40Z jilles $");
+
+#include <stdlib.h>
+#include "shell.h"
+#include "output.h"
+#include "error.h"
+#include "memalloc.h"
+#include "mystring.h"
+#include "alias.h"
+#include "options.h"	/* XXX for argptr (should remove?) */
+#include "builtins.h"
+
+#define ATABSIZE 39
+
+static struct alias *atab[ATABSIZE];
+static int aliases;
+
+static void setalias(const char *, const char *);
+static int unalias(const char *);
+static struct alias **hashalias(const char *);
+
+static
+void
+setalias(const char *name, const char *val)
+{
+	struct alias *ap, **app;
+
+	app = hashalias(name);
+	for (ap = *app; ap; ap = ap->next) {
+		if (equal(name, ap->name)) {
+			INTOFF;
+			ckfree(ap->val);
+			ap->val	= savestr(val);
+			INTON;
+			return;
+		}
+	}
+	/* not found */
+	INTOFF;
+	ap = ckmalloc(sizeof (struct alias));
+	ap->name = savestr(name);
+	ap->val = savestr(val);
+	ap->flag = 0;
+	ap->next = *app;
+	*app = ap;
+	aliases++;
+	INTON;
+}
+
+static int
+unalias(const char *name)
+{
+	struct alias *ap, **app;
+
+	app = hashalias(name);
+
+	for (ap = *app; ap; app = &(ap->next), ap = ap->next) {
+		if (equal(name, ap->name)) {
+			/*
+			 * if the alias is currently in use (i.e. its
+			 * buffer is being used by the input routine) we
+			 * just null out the name instead of freeing it.
+			 * We could clear it out later, but this situation
+			 * is so rare that it hardly seems worth it.
+			 */
+			if (ap->flag & ALIASINUSE)
+				*ap->name = '\0';
+			else {
+				INTOFF;
+				*app = ap->next;
+				ckfree(ap->name);
+				ckfree(ap->val);
+				ckfree(ap);
+				INTON;
+			}
+			aliases--;
+			return (0);
+		}
+	}
+
+	return (1);
+}
+
+static void
+rmaliases(void)
+{
+	struct alias *ap, *tmp;
+	int i;
+
+	INTOFF;
+	for (i = 0; i < ATABSIZE; i++) {
+		ap = atab[i];
+		atab[i] = NULL;
+		while (ap) {
+			ckfree(ap->name);
+			ckfree(ap->val);
+			tmp = ap;
+			ap = ap->next;
+			ckfree(tmp);
+		}
+	}
+	aliases = 0;
+	INTON;
+}
+
+struct alias *
+lookupalias(const char *name, int check)
+{
+	struct alias *ap = *hashalias(name);
+
+	for (; ap; ap = ap->next) {
+		if (equal(name, ap->name)) {
+			if (check && (ap->flag & ALIASINUSE))
+				return (NULL);
+			return (ap);
+		}
+	}
+
+	return (NULL);
+}
+
+static int
+comparealiases(const void *p1, const void *p2)
+{
+	const struct alias *const *a1 = p1;
+	const struct alias *const *a2 = p2;
+
+	return strcmp((*a1)->name, (*a2)->name);
+}
+
+static void
+printalias(const struct alias *a)
+{
+	out1fmt("%s=", a->name);
+	out1qstr(a->val);
+	out1c('\n');
+}
+
+static void
+printaliases(void)
+{
+	int i, j;
+	struct alias **sorted, *ap;
+
+	INTOFF;
+	sorted = ckmalloc(aliases * sizeof(*sorted));
+	j = 0;
+	for (i = 0; i < ATABSIZE; i++)
+		for (ap = atab[i]; ap; ap = ap->next)
+			if (*ap->name != '\0')
+				sorted[j++] = ap;
+	qsort(sorted, aliases, sizeof(*sorted), comparealiases);
+	for (i = 0; i < aliases; i++) {
+		printalias(sorted[i]);
+		if (int_pending())
+			break;
+	}
+	ckfree(sorted);
+	INTON;
+}
+
+int
+aliascmd(int argc __unused, char **argv __unused)
+{
+	char *n, *v;
+	int ret = 0;
+	struct alias *ap;
+
+	nextopt("");
+
+	if (*argptr == NULL) {
+		printaliases();
+		return (0);
+	}
+	while ((n = *argptr++) != NULL) {
+		if ((v = strchr(n+1, '=')) == NULL) /* n+1: funny ksh stuff */
+			if ((ap = lookupalias(n, 0)) == NULL) {
+				warning("%s: not found", n);
+				ret = 1;
+			} else
+				printalias(ap);
+		else {
+			*v++ = '\0';
+			setalias(n, v);
+		}
+	}
+
+	return (ret);
+}
+
+int
+unaliascmd(int argc __unused, char **argv __unused)
+{
+	int i;
+
+	while ((i = nextopt("a")) != '\0') {
+		if (i == 'a') {
+			rmaliases();
+			return (0);
+		}
+	}
+	for (i = 0; *argptr; argptr++)
+		i |= unalias(*argptr);
+
+	return (i);
+}
+
+static struct alias **
+hashalias(const char *p)
+{
+	unsigned int hashval;
+
+	hashval = *p << 4;
+	while (*p)
+		hashval+= *p++;
+	return &atab[hashval % ATABSIZE];
+}
diff --git a/external/sh/alias.h b/external/sh/alias.h
new file mode 100644
index 00000000..95a20eae
--- /dev/null
+++ b/external/sh/alias.h
@@ -0,0 +1,45 @@
+/*-
+ * Copyright (c) 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)alias.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: head/bin/sh/alias.h 223060 2011-06-13 21:03:27Z jilles $
+ */
+
+#define ALIASINUSE	1
+
+struct alias {
+	struct alias *next;
+	char *name;
+	char *val;
+	int flag;
+};
+
+struct alias *lookupalias(const char *, int);
diff --git a/external/sh/arith.h b/external/sh/arith.h
new file mode 100644
index 00000000..3771fe10
--- /dev/null
+++ b/external/sh/arith.h
@@ -0,0 +1,38 @@
+/*-
+ * Copyright (c) 1995
+ *      The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)arith.h	1.1 (Berkeley) 5/4/95
+ * $FreeBSD: head/bin/sh/arith.h 223060 2011-06-13 21:03:27Z jilles $
+ */
+
+#include "shell.h"
+
+#define DIGITS(var) (3 + (2 + CHAR_BIT * sizeof((var))) / 3)
+
+arith_t arith(const char *);
+void arith_lex_reset(void);
diff --git a/external/sh/arith_yacc.c b/external/sh/arith_yacc.c
new file mode 100644
index 00000000..20e1e43e
--- /dev/null
+++ b/external/sh/arith_yacc.c
@@ -0,0 +1,381 @@
+/*-
+ * Copyright (c) 1993
+ *	The Regents of the University of California.  All rights reserved.
+ * Copyright (c) 2007
+ *	Herbert Xu <herbert@gondor.apana.org.au>.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: head/bin/sh/arith_yacc.c 270246 2014-08-20 20:15:43Z jilles $");
+
+#include <limits.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include "arith.h"
+#include "arith_yacc.h"
+#include "expand.h"
+#include "shell.h"
+#include "error.h"
+#include "memalloc.h"
+#include "output.h"
+#include "options.h"
+#include "var.h"
+
+#if ARITH_BOR + 11 != ARITH_BORASS || ARITH_ASS + 11 != ARITH_EQ
+#error Arithmetic tokens are out of order.
+#endif
+
+static const char *arith_startbuf;
+
+const char *arith_buf;
+union yystype yylval;
+
+static int last_token;
+
+#define ARITH_PRECEDENCE(op, prec) [op - ARITH_BINOP_MIN] = prec
+
+static const char prec[ARITH_BINOP_MAX - ARITH_BINOP_MIN] = {
+	ARITH_PRECEDENCE(ARITH_MUL, 0),
+	ARITH_PRECEDENCE(ARITH_DIV, 0),
+	ARITH_PRECEDENCE(ARITH_REM, 0),
+	ARITH_PRECEDENCE(ARITH_ADD, 1),
+	ARITH_PRECEDENCE(ARITH_SUB, 1),
+	ARITH_PRECEDENCE(ARITH_LSHIFT, 2),
+	ARITH_PRECEDENCE(ARITH_RSHIFT, 2),
+	ARITH_PRECEDENCE(ARITH_LT, 3),
+	ARITH_PRECEDENCE(ARITH_LE, 3),
+	ARITH_PRECEDENCE(ARITH_GT, 3),
+	ARITH_PRECEDENCE(ARITH_GE, 3),
+	ARITH_PRECEDENCE(ARITH_EQ, 4),
+	ARITH_PRECEDENCE(ARITH_NE, 4),
+	ARITH_PRECEDENCE(ARITH_BAND, 5),
+	ARITH_PRECEDENCE(ARITH_BXOR, 6),
+	ARITH_PRECEDENCE(ARITH_BOR, 7),
+};
+
+#define ARITH_MAX_PREC 8
+
+int letcmd(int, char **);
+
+static __dead2 void yyerror(const char *s)
+{
+	error("arithmetic expression: %s: \"%s\"", s, arith_startbuf);
+	/* NOTREACHED */
+}
+
+static arith_t arith_lookupvarint(char *varname)
+{
+	const char *str;
+	char *p;
+	arith_t result;
+
+	str = lookupvar(varname);
+	if (uflag && str == NULL)
+		yyerror("variable not set");
+	if (str == NULL || *str == '\0')
+		str = "0";
+	errno = 0;
+	result = strtoarith_t(str, &p, 0);
+	if (errno != 0 || *p != '\0')
+		yyerror("variable conversion error");
+	return result;
+}
+
+static inline int arith_prec(int op)
+{
+	return prec[op - ARITH_BINOP_MIN];
+}
+
+static inline int higher_prec(int op1, int op2)
+{
+	return arith_prec(op1) < arith_prec(op2);
+}
+
+static arith_t do_binop(int op, arith_t a, arith_t b)
+{
+
+	switch (op) {
+	default:
+	case ARITH_REM:
+	case ARITH_DIV:
+		if (!b)
+			yyerror("division by zero");
+		if (a == ARITH_MIN && b == -1)
+			yyerror("divide error");
+		return op == ARITH_REM ? a % b : a / b;
+	case ARITH_MUL:
+		return (uintmax_t)a * (uintmax_t)b;
+	case ARITH_ADD:
+		return (uintmax_t)a + (uintmax_t)b;
+	case ARITH_SUB:
+		return (uintmax_t)a - (uintmax_t)b;
+	case ARITH_LSHIFT:
+		return (uintmax_t)a << (b & (sizeof(uintmax_t) * CHAR_BIT - 1));
+	case ARITH_RSHIFT:
+		return a >> (b & (sizeof(uintmax_t) * CHAR_BIT - 1));
+	case ARITH_LT:
+		return a < b;
+	case ARITH_LE:
+		return a <= b;
+	case ARITH_GT:
+		return a > b;
+	case ARITH_GE:
+		return a >= b;
+	case ARITH_EQ:
+		return a == b;
+	case ARITH_NE:
+		return a != b;
+	case ARITH_BAND:
+		return a & b;
+	case ARITH_BXOR:
+		return a ^ b;
+	case ARITH_BOR:
+		return a | b;
+	}
+}
+
+static arith_t assignment(int var, int noeval);
+
+static arith_t primary(int token, union yystype *val, int op, int noeval)
+{
+	arith_t result;
+
+again:
+	switch (token) {
+	case ARITH_LPAREN:
+		result = assignment(op, noeval);
+		if (last_token != ARITH_RPAREN)
+			yyerror("expecting ')'");
+		last_token = yylex();
+		return result;
+	case ARITH_NUM:
+		last_token = op;
+		return val->val;
+	case ARITH_VAR:
+		last_token = op;
+		return noeval ? val->val : arith_lookupvarint(val->name);
+	case ARITH_ADD:
+		token = op;
+		*val = yylval;
+		op = yylex();
+		goto again;
+	case ARITH_SUB:
+		*val = yylval;
+		return -primary(op, val, yylex(), noeval);
+	case ARITH_NOT:
+		*val = yylval;
+		return !primary(op, val, yylex(), noeval);
+	case ARITH_BNOT:
+		*val = yylval;
+		return ~primary(op, val, yylex(), noeval);
+	default:
+		yyerror("expecting primary");
+	}
+}
+
+static arith_t binop2(arith_t a, int op, int precedence, int noeval)
+{
+	for (;;) {
+		union yystype val;
+		arith_t b;
+		int op2;
+		int token;
+
+		token = yylex();
+		val = yylval;
+
+		b = primary(token, &val, yylex(), noeval);
+
+		op2 = last_token;
+		if (op2 >= ARITH_BINOP_MIN && op2 < ARITH_BINOP_MAX &&
+		    higher_prec(op2, op)) {
+			b = binop2(b, op2, arith_prec(op), noeval);
+			op2 = last_token;
+		}
+
+		a = noeval ? b : do_binop(op, a, b);
+
+		if (op2 < ARITH_BINOP_MIN || op2 >= ARITH_BINOP_MAX ||
+		    arith_prec(op2) >= precedence)
+			return a;
+
+		op = op2;
+	}
+}
+
+static arith_t binop(int token, union yystype *val, int op, int noeval)
+{
+	arith_t a = primary(token, val, op, noeval);
+
+	op = last_token;
+	if (op < ARITH_BINOP_MIN || op >= ARITH_BINOP_MAX)
+		return a;
+
+	return binop2(a, op, ARITH_MAX_PREC, noeval);
+}
+
+static arith_t and(int token, union yystype *val, int op, int noeval)
+{
+	arith_t a = binop(token, val, op, noeval);
+	arith_t b;
+
+	op = last_token;
+	if (op != ARITH_AND)
+		return a;
+
+	token = yylex();
+	*val = yylval;
+
+	b = and(token, val, yylex(), noeval | !a);
+
+	return a && b;
+}
+
+static arith_t or(int token, union yystype *val, int op, int noeval)
+{
+	arith_t a = and(token, val, op, noeval);
+	arith_t b;
+
+	op = last_token;
+	if (op != ARITH_OR)
+		return a;
+
+	token = yylex();
+	*val = yylval;
+
+	b = or(token, val, yylex(), noeval | !!a);
+
+	return a || b;
+}
+
+static arith_t cond(int token, union yystype *val, int op, int noeval)
+{
+	arith_t a = or(token, val, op, noeval);
+	arith_t b;
+	arith_t c;
+
+	if (last_token != ARITH_QMARK)
+		return a;
+
+	b = assignment(yylex(), noeval | !a);
+
+	if (last_token != ARITH_COLON)
+		yyerror("expecting ':'");
+
+	token = yylex();
+	*val = yylval;
+
+	c = cond(token, val, yylex(), noeval | !!a);
+
+	return a ? b : c;
+}
+
+static arith_t assignment(int var, int noeval)
+{
+	union yystype val = yylval;
+	int op = yylex();
+	arith_t result;
+	char sresult[DIGITS(result) + 1];
+
+	if (var != ARITH_VAR)
+		return cond(var, &val, op, noeval);
+
+	if (op != ARITH_ASS && (op < ARITH_ASS_MIN || op >= ARITH_ASS_MAX))
+		return cond(var, &val, op, noeval);
+
+	result = assignment(yylex(), noeval);
+	if (noeval)
+		return result;
+
+	if (op != ARITH_ASS)
+		result = do_binop(op - 11, arith_lookupvarint(val.name), result);
+	snprintf(sresult, sizeof(sresult), ARITH_FORMAT_STR, result);
+	setvar(val.name, sresult, 0);
+	return result;
+}
+
+arith_t arith(const char *s)
+{
+	struct stackmark smark;
+	arith_t result;
+
+	setstackmark(&smark);
+
+	arith_buf = arith_startbuf = s;
+
+	result = assignment(yylex(), 0);
+
+	if (last_token)
+		yyerror("expecting EOF");
+
+	popstackmark(&smark);
+
+	return result;
+}
+
+/*
+ *  The exp(1) builtin.
+ */
+int
+letcmd(int argc, char **argv)
+{
+	const char *p;
+	char *concat;
+	char **ap;
+	arith_t i;
+
+	if (argc > 1) {
+		p = argv[1];
+		if (argc > 2) {
+			/*
+			 * Concatenate arguments.
+			 */
+			STARTSTACKSTR(concat);
+			ap = argv + 2;
+			for (;;) {
+				while (*p)
+					STPUTC(*p++, concat);
+				if ((p = *ap++) == NULL)
+					break;
+				STPUTC(' ', concat);
+			}
+			STPUTC('\0', concat);
+			p = grabstackstr(concat);
+		}
+	} else
+		p = "";
+
+	i = arith(p);
+
+	out1fmt(ARITH_FORMAT_STR "\n", i);
+	return !i;
+}
diff --git a/external/sh/arith_yacc.h b/external/sh/arith_yacc.h
new file mode 100644
index 00000000..d386886a
--- /dev/null
+++ b/external/sh/arith_yacc.h
@@ -0,0 +1,93 @@
+/*-
+ * Copyright (c) 1993
+ *	The Regents of the University of California.  All rights reserved.
+ * Copyright (c) 2007
+ *	Herbert Xu <herbert@gondor.apana.org.au>.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD: head/bin/sh/arith_yacc.h 279503 2015-03-01 21:46:55Z jilles $
+ */
+
+#define ARITH_ASS 1
+
+#define ARITH_OR 2
+#define ARITH_AND 3
+#define ARITH_BAD 4
+#define ARITH_NUM 5
+#define ARITH_VAR 6
+#define ARITH_NOT 7
+
+#define ARITH_BINOP_MIN 8
+#define ARITH_LE 8
+#define ARITH_GE 9
+#define ARITH_LT 10
+#define ARITH_GT 11
+#define ARITH_EQ 12
+#define ARITH_REM 13
+#define ARITH_BAND 14
+#define ARITH_LSHIFT 15
+#define ARITH_RSHIFT 16
+#define ARITH_MUL 17
+#define ARITH_ADD 18
+#define ARITH_BOR 19
+#define ARITH_SUB 20
+#define ARITH_BXOR 21
+#define ARITH_DIV 22
+#define ARITH_NE 23
+#define ARITH_BINOP_MAX 24
+
+#define ARITH_ASS_MIN 24
+#define ARITH_REMASS 24
+#define ARITH_BANDASS 25
+#define ARITH_LSHIFTASS 26
+#define ARITH_RSHIFTASS 27
+#define ARITH_MULASS 28
+#define ARITH_ADDASS 29
+#define ARITH_BORASS 30
+#define ARITH_SUBASS 31
+#define ARITH_BXORASS 32
+#define ARITH_DIVASS 33
+#define ARITH_ASS_MAX 34
+
+#define ARITH_LPAREN 34
+#define ARITH_RPAREN 35
+#define ARITH_BNOT 36
+#define ARITH_QMARK 37
+#define ARITH_COLON 38
+
+extern const char *arith_buf;
+
+union yystype {
+	arith_t val;
+	char *name;
+};
+
+extern union yystype yylval;
+
+int yylex(void);
diff --git a/external/sh/arith_yylex.c b/external/sh/arith_yylex.c
new file mode 100644
index 00000000..99368523
--- /dev/null
+++ b/external/sh/arith_yylex.c
@@ -0,0 +1,248 @@
+/*-
+ * Copyright (c) 2002
+ *	Herbert Xu.
+ * Copyright (c) 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: head/bin/sh/arith_yylex.c 279503 2015-03-01 21:46:55Z jilles $");
+
+#include <inttypes.h>
+#include <stdlib.h>
+#include <string.h>
+#include "shell.h"
+#include "arith_yacc.h"
+#include "expand.h"
+#include "error.h"
+#include "memalloc.h"
+#include "parser.h"
+#include "syntax.h"
+
+#if ARITH_BOR + 11 != ARITH_BORASS || ARITH_ASS + 11 != ARITH_EQ
+#error Arithmetic tokens are out of order.
+#endif
+
+int
+yylex(void)
+{
+	int value;
+	const char *buf = arith_buf;
+	char *end;
+	const char *p;
+
+	for (;;) {
+		value = *buf;
+		switch (value) {
+		case ' ':
+		case '\t':
+		case '\n':
+			buf++;
+			continue;
+		default:
+			return ARITH_BAD;
+		case '0':
+		case '1':
+		case '2':
+		case '3':
+		case '4':
+		case '5':
+		case '6':
+		case '7':
+		case '8':
+		case '9':
+			yylval.val = strtoarith_t(buf, &end, 0);
+			arith_buf = end;
+			return ARITH_NUM;
+		case 'A':
+		case 'B':
+		case 'C':
+		case 'D':
+		case 'E':
+		case 'F':
+		case 'G':
+		case 'H':
+		case 'I':
+		case 'J':
+		case 'K':
+		case 'L':
+		case 'M':
+		case 'N':
+		case 'O':
+		case 'P':
+		case 'Q':
+		case 'R':
+		case 'S':
+		case 'T':
+		case 'U':
+		case 'V':
+		case 'W':
+		case 'X':
+		case 'Y':
+		case 'Z':
+		case '_':
+		case 'a':
+		case 'b':
+		case 'c':
+		case 'd':
+		case 'e':
+		case 'f':
+		case 'g':
+		case 'h':
+		case 'i':
+		case 'j':
+		case 'k':
+		case 'l':
+		case 'm':
+		case 'n':
+		case 'o':
+		case 'p':
+		case 'q':
+		case 'r':
+		case 's':
+		case 't':
+		case 'u':
+		case 'v':
+		case 'w':
+		case 'x':
+		case 'y':
+		case 'z':
+			p = buf;
+			while (buf++, is_in_name(*buf))
+				;
+			yylval.name = stalloc(buf - p + 1);
+			memcpy(yylval.name, p, buf - p);
+			yylval.name[buf - p] = '\0';
+			value = ARITH_VAR;
+			goto out;
+		case '=':
+			value += ARITH_ASS - '=';
+checkeq:
+			buf++;
+checkeqcur:
+			if (*buf != '=')
+				goto out;
+			value += 11;
+			break;
+		case '>':
+			switch (*++buf) {
+			case '=':
+				value += ARITH_GE - '>';
+				break;
+			case '>':
+				value += ARITH_RSHIFT - '>';
+				goto checkeq;
+			default:
+				value += ARITH_GT - '>';
+				goto out;
+			}
+			break;
+		case '<':
+			switch (*++buf) {
+			case '=':
+				value += ARITH_LE - '<';
+				break;
+			case '<':
+				value += ARITH_LSHIFT - '<';
+				goto checkeq;
+			default:
+				value += ARITH_LT - '<';
+				goto out;
+			}
+			break;
+		case '|':
+			if (*++buf != '|') {
+				value += ARITH_BOR - '|';
+				goto checkeqcur;
+			}
+			value += ARITH_OR - '|';
+			break;
+		case '&':
+			if (*++buf != '&') {
+				value += ARITH_BAND - '&';
+				goto checkeqcur;
+			}
+			value += ARITH_AND - '&';
+			break;
+		case '!':
+			if (*++buf != '=') {
+				value += ARITH_NOT - '!';
+				goto out;
+			}
+			value += ARITH_NE - '!';
+			break;
+		case 0:
+			goto out;
+		case '(':
+			value += ARITH_LPAREN - '(';
+			break;
+		case ')':
+			value += ARITH_RPAREN - ')';
+			break;
+		case '*':
+			value += ARITH_MUL - '*';
+			goto checkeq;
+		case '/':
+			value += ARITH_DIV - '/';
+			goto checkeq;
+		case '%':
+			value += ARITH_REM - '%';
+			goto checkeq;
+		case '+':
+			if (buf[1] == '+')
+				return ARITH_BAD;
+			value += ARITH_ADD - '+';
+			goto checkeq;
+		case '-':
+			if (buf[1] == '-')
+				return ARITH_BAD;
+			value += ARITH_SUB - '-';
+			goto checkeq;
+		case '~':
+			value += ARITH_BNOT - '~';
+			break;
+		case '^':
+			value += ARITH_BXOR - '^';
+			goto checkeq;
+		case '?':
+			value += ARITH_QMARK - '?';
+			break;
+		case ':':
+			value += ARITH_COLON - ':';
+			break;
+		}
+		break;
+	}
+
+	buf++;
+out:
+	arith_buf = buf;
+	return value;
+}
diff --git a/external/sh/bltin/bltin.h b/external/sh/bltin/bltin.h
new file mode 100644
index 00000000..b79cc43a
--- /dev/null
+++ b/external/sh/bltin/bltin.h
@@ -0,0 +1,79 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)bltin.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: head/bin/sh/bltin/bltin.h 279503 2015-03-01 21:46:55Z jilles $
+ */
+
+/*
+ * This file is included by programs which are optionally built into the
+ * shell.  If SHELL is defined, we try to map the standard UNIX library
+ * routines to ash routines using defines.
+ */
+
+#include "../shell.h"
+#include "../mystring.h"
+#ifdef SHELL
+#include "../error.h"
+#include "../output.h"
+#include "builtins.h"
+#define FILE struct output
+#undef stdout
+#define stdout out1
+#undef stderr
+#define stderr out2
+#define printf out1fmt
+#undef putc
+#define putc(c, file)	outc(c, file)
+#undef putchar
+#define putchar(c)	out1c(c)
+#define fprintf outfmt
+#define fputs outstr
+#define fwrite(ptr, size, nmemb, file) outbin(ptr, (size) * (nmemb), file)
+#define fflush flushout
+#define INITARGS(argv)
+#define warnx warning
+#define warn(fmt, ...) warning(fmt ": %s", __VA_ARGS__, strerror(errno))
+#define errx(exitstatus, ...) error(__VA_ARGS__)
+
+#else
+#undef NULL
+#include <stdio.h>
+#undef main
+#define INITARGS(argv)	if ((commandname = argv[0]) == NULL) {fputs("Argc is zero\n", stderr); exit(2);} else
+#endif
+
+#include <unistd.h>
+
+pointer stalloc(int);
+int killjob(const char *, int);
+
+extern char *commandname;
diff --git a/external/sh/bltin/echo.c b/external/sh/bltin/echo.c
new file mode 100644
index 00000000..3de6589e
--- /dev/null
+++ b/external/sh/bltin/echo.c
@@ -0,0 +1,107 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)echo.c	8.2 (Berkeley) 5/4/95
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: head/bin/sh/bltin/echo.c 127958 2004-04-06 20:06:54Z markm $");
+
+/*
+ * Echo command.
+ */
+
+#define main echocmd
+
+#include "bltin.h"
+
+/* #define eflag 1 */
+
+int
+main(int argc, char *argv[])
+{
+	char **ap;
+	char *p;
+	char c;
+	int count;
+	int nflag = 0;
+#ifndef eflag
+	int eflag = 0;
+#endif
+
+	ap = argv;
+	if (argc)
+		ap++;
+	if ((p = *ap) != NULL) {
+		if (equal(p, "-n")) {
+			nflag++;
+			ap++;
+		} else if (equal(p, "-e")) {
+#ifndef eflag
+			eflag++;
+#endif
+			ap++;
+		}
+	}
+	while ((p = *ap++) != NULL) {
+		while ((c = *p++) != '\0') {
+			if (c == '\\' && eflag) {
+				switch (*p++) {
+				case 'a':  c = '\a';  break;
+				case 'b':  c = '\b';  break;
+				case 'c':  return 0;		/* exit */
+				case 'e':  c = '\033';  break;
+				case 'f':  c = '\f';  break;
+				case 'n':  c = '\n';  break;
+				case 'r':  c = '\r';  break;
+				case 't':  c = '\t';  break;
+				case 'v':  c = '\v';  break;
+				case '\\':  break;		/* c = '\\' */
+				case '0':
+					c = 0;
+					count = 3;
+					while (--count >= 0 && (unsigned)(*p - '0') < 8)
+						c = (c << 3) + (*p++ - '0');
+					break;
+				default:
+					p--;
+					break;
+				}
+			}
+			putchar(c);
+		}
+		if (*ap)
+			putchar(' ');
+	}
+	if (! nflag)
+		putchar('\n');
+	return 0;
+}
diff --git a/external/sh/builtins.c b/external/sh/builtins.c
new file mode 100644
index 00000000..cabca99a
--- /dev/null
+++ b/external/sh/builtins.c
@@ -0,0 +1,101 @@
+/*
+ * This file was generated by the mkbuiltins program.
+ */
+
+#include <stdlib.h>
+#include "shell.h"
+#include "builtins.h"
+
+int (*const builtinfunc[])(int, char **) = {
+	bltincmd,
+	aliascmd,
+	bgcmd,
+	bindcmd,
+	breakcmd,
+	cdcmd,
+	commandcmd,
+	dotcmd,
+	echocmd,
+	evalcmd,
+	execcmd,
+	exitcmd,
+	letcmd,
+	exportcmd,
+	falsecmd,
+	fgcmd,
+	getoptscmd,
+	hashcmd,
+	histcmd,
+	jobidcmd,
+	jobscmd,
+	killcmd,
+	localcmd,
+	printfcmd,
+	pwdcmd,
+	readcmd,
+	returncmd,
+	setcmd,
+	setvarcmd,
+	shiftcmd,
+	testcmd,
+	timescmd,
+	trapcmd,
+	truecmd,
+	typecmd,
+	ulimitcmd,
+	umaskcmd,
+	unaliascmd,
+	unsetcmd,
+	waitcmd,
+	wordexpcmd,
+};
+
+const struct builtincmd builtincmd[] = {
+	{ "builtin", 0, 0 },
+	{ "alias", 1, 0 },
+	{ "bg", 2, 0 },
+	{ "bind", 3, 0 },
+	{ "break", 4, 1 },
+	{ "continue", 4, 1 },
+	{ "cd", 5, 0 },
+	{ "chdir", 5, 0 },
+	{ "command", 6, 0 },
+	{ ".", 7, 1 },
+	{ "echo", 8, 0 },
+	{ "eval", 9, 1 },
+	{ "exec", 10, 1 },
+	{ "exit", 11, 1 },
+	{ "let", 12, 0 },
+	{ "export", 13, 1 },
+	{ "readonly", 13, 1 },
+	{ "false", 14, 0 },
+	{ "fg", 15, 0 },
+	{ "getopts", 16, 0 },
+	{ "hash", 17, 0 },
+	{ "fc", 18, 0 },
+	{ "jobid", 19, 0 },
+	{ "jobs", 20, 0 },
+	{ "kill", 21, 0 },
+	{ "local", 22, 0 },
+	{ "printf", 23, 0 },
+	{ "pwd", 24, 0 },
+	{ "read", 25, 0 },
+	{ "return", 26, 1 },
+	{ "set", 27, 1 },
+	{ "setvar", 28, 0 },
+	{ "shift", 29, 1 },
+	{ "test", 30, 0 },
+	{ "[", 30, 0 },
+	{ "times", 31, 1 },
+	{ "trap", 32, 1 },
+	{ ":", 33, 1 },
+	{ "true", 33, 0 },
+	{ "type", 34, 0 },
+	{ "ulimit", 35, 0 },
+	{ "umask", 36, 0 },
+	{ "unalias", 37, 0 },
+	{ "unset", 38, 1 },
+	{ "wait", 39, 0 },
+	{ "wordexp", 40, 0 },
+	{ NULL, 0, 0 }
+};
diff --git a/external/sh/builtins.h b/external/sh/builtins.h
new file mode 100644
index 00000000..cade05ff
--- /dev/null
+++ b/external/sh/builtins.h
@@ -0,0 +1,97 @@
+/*
+ * This file was generated by the mkbuiltins program.
+ */
+
+#include <sys/cdefs.h>
+#define BLTINCMD 0
+#define ALIASCMD 1
+#define BGCMD 2
+#define BINDCMD 3
+#define BREAKCMD 4
+#define CDCMD 5
+#define COMMANDCMD 6
+#define DOTCMD 7
+#define ECHOCMD 8
+#define EVALCMD 9
+#define EXECCMD 10
+#define EXITCMD 11
+#define LETCMD 12
+#define EXPORTCMD 13
+#define FALSECMD 14
+#define FGCMD 15
+#define GETOPTSCMD 16
+#define HASHCMD 17
+#define HISTCMD 18
+#define JOBIDCMD 19
+#define JOBSCMD 20
+#define KILLCMD 21
+#define LOCALCMD 22
+#define PRINTFCMD 23
+#define PWDCMD 24
+#define READCMD 25
+#define RETURNCMD 26
+#define SETCMD 27
+#define SETVARCMD 28
+#define SHIFTCMD 29
+#define TESTCMD 30
+#define TIMESCMD 31
+#define TRAPCMD 32
+#define TRUECMD 33
+#define TYPECMD 34
+#define ULIMITCMD 35
+#define UMASKCMD 36
+#define UNALIASCMD 37
+#define UNSETCMD 38
+#define WAITCMD 39
+#define WORDEXPCMD 40
+
+struct builtincmd {
+      const char *name;
+      int code;
+      int special;
+};
+
+extern int (*const builtinfunc[])(int, char **);
+extern const struct builtincmd builtincmd[];
+
+int bltincmd(int, char **);
+int aliascmd(int, char **);
+int bgcmd(int, char **);
+int bindcmd(int, char **);
+int breakcmd(int, char **);
+int cdcmd(int, char **);
+int commandcmd(int, char **);
+int dotcmd(int, char **);
+int echocmd(int, char **);
+int evalcmd(int, char **);
+int execcmd(int, char **);
+int exitcmd(int, char **);
+int letcmd(int, char **);
+int exportcmd(int, char **);
+int falsecmd(int, char **);
+int fgcmd(int, char **);
+int getoptscmd(int, char **);
+int hashcmd(int, char **);
+int histcmd(int, char **);
+int jobidcmd(int, char **);
+int jobscmd(int, char **);
+int killcmd(int, char **);
+int localcmd(int, char **);
+int printfcmd(int, char **);
+int pwdcmd(int, char **);
+int readcmd(int, char **);
+int returncmd(int, char **);
+int setcmd(int, char **);
+int setvarcmd(int, char **);
+int shiftcmd(int, char **);
+int testcmd(int, char **);
+int timescmd(int, char **);
+int trapcmd(int, char **);
+int truecmd(int, char **);
+int typecmd(int, char **);
+int ulimitcmd(int, char **);
+int umaskcmd(int, char **);
+int unaliascmd(int, char **);
+int unsetcmd(int, char **);
+int waitcmd(int, char **);
+int wordexpcmd(int, char **);
diff --git a/external/sh/cd.c b/external/sh/cd.c
new file mode 100644
index 00000000..596d782b
--- /dev/null
+++ b/external/sh/cd.c
@@ -0,0 +1,421 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)cd.c	8.2 (Berkeley) 5/4/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: head/bin/sh/cd.c 278820 2015-02-15 21:47:43Z jilles $");
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <limits.h>
+
+/*
+ * The cd and pwd commands.
+ */
+
+#include "shell.h"
+#include "var.h"
+#include "nodes.h"	/* for jobs.h */
+#include "jobs.h"
+#include "options.h"
+#include "output.h"
+#include "memalloc.h"
+#include "error.h"
+#include "exec.h"
+#include "redir.h"
+#include "mystring.h"
+#include "show.h"
+#include "cd.h"
+#include "builtins.h"
+
+static int cdlogical(char *);
+static int cdphysical(char *);
+static int docd(char *, int, int);
+static char *getcomponent(void);
+static char *findcwd(char *);
+static void updatepwd(char *);
+static char *getpwd(void);
+static char *getpwd2(void);
+
+static char *curdir = NULL;	/* current working directory */
+static char *prevdir;		/* previous working directory */
+static char *cdcomppath;
+
+int
+cdcmd(int argc __unused, char **argv __unused)
+{
+	const char *dest;
+	const char *path;
+	char *p;
+	struct stat statb;
+	int ch, phys, print = 0, getcwderr = 0;
+	int rc;
+	int errno1 = ENOENT;
+
+	phys = Pflag;
+	while ((ch = nextopt("eLP")) != '\0') {
+		switch (ch) {
+		case 'e':
+			getcwderr = 1;
+			break;
+		case 'L':
+			phys = 0;
+			break;
+		case 'P':
+			phys = 1;
+			break;
+		}
+	}
+
+	if (*argptr != NULL && argptr[1] != NULL)
+		error("too many arguments");
+
+	if ((dest = *argptr) == NULL && (dest = bltinlookup("HOME", 1)) == NULL)
+		error("HOME not set");
+	if (*dest == '\0')
+		dest = ".";
+	if (dest[0] == '-' && dest[1] == '\0') {
+		dest = prevdir ? prevdir : curdir;
+		if (dest)
+			print = 1;
+		else
+			dest = ".";
+	}
+	if (dest[0] == '/' ||
+	    (dest[0] == '.' && (dest[1] == '/' || dest[1] == '\0')) ||
+	    (dest[0] == '.' && dest[1] == '.' && (dest[2] == '/' || dest[2] == '\0')) ||
+	    (path = bltinlookup("CDPATH", 1)) == NULL)
+		path = "";
+	while ((p = padvance(&path, dest)) != NULL) {
+		if (stat(p, &statb) < 0) {
+			if (errno != ENOENT)
+				errno1 = errno;
+		} else if (!S_ISDIR(statb.st_mode))
+			errno1 = ENOTDIR;
+		else {
+			if (!print) {
+				/*
+				 * XXX - rethink
+				 */
+				if (p[0] == '.' && p[1] == '/' && p[2] != '\0')
+					print = strcmp(p + 2, dest);
+				else
+					print = strcmp(p, dest);
+			}
+			rc = docd(p, print, phys);
+			if (rc >= 0)
+				return getcwderr ? rc : 0;
+			if (errno != ENOENT)
+				errno1 = errno;
+		}
+	}
+	error("%s: %s", dest, strerror(errno1));
+	/*NOTREACHED*/
+	return 0;
+}
+
+
+/*
+ * Actually change the directory.  In an interactive shell, print the
+ * directory name if "print" is nonzero.
+ */
+static int
+docd(char *dest, int print, int phys)
+{
+	int rc;
+
+	TRACE(("docd(\"%s\", %d, %d) called\n", dest, print, phys));
+
+	/* If logical cd fails, fall back to physical. */
+	if ((phys || (rc = cdlogical(dest)) < 0) && (rc = cdphysical(dest)) < 0)
+		return (-1);
+
+	if (print && iflag && curdir)
+		out1fmt("%s\n", curdir);
+
+	return (rc);
+}
+
+static int
+cdlogical(char *dest)
+{
+	char *p;
+	char *q;
+	char *component;
+	struct stat statb;
+	int first;
+	int badstat;
+
+	/*
+	 *  Check each component of the path. If we find a symlink or
+	 *  something we can't stat, clear curdir to force a getcwd()
+	 *  next time we get the value of the current directory.
+	 */
+	badstat = 0;
+	cdcomppath = stsavestr(dest);
+	STARTSTACKSTR(p);
+	if (*dest == '/') {
+		STPUTC('/', p);
+		cdcomppath++;
+	}
+	first = 1;
+	while ((q = getcomponent()) != NULL) {
+		if (q[0] == '\0' || (q[0] == '.' && q[1] == '\0'))
+			continue;
+		if (! first)
+			STPUTC('/', p);
+		first = 0;
+		component = q;
+		STPUTS(q, p);
+		if (equal(component, ".."))
+			continue;
+		STACKSTRNUL(p);
+		if (lstat(stackblock(), &statb) < 0) {
+			badstat = 1;
+			break;
+		}
+	}
+
+	INTOFF;
+	if ((p = findcwd(badstat ? NULL : dest)) == NULL || chdir(p) < 0) {
+		INTON;
+		return (-1);
+	}
+	updatepwd(p);
+	INTON;
+	return (0);
+}
+
+static int
+cdphysical(char *dest)
+{
+	char *p;
+	int rc = 0;
+
+	INTOFF;
+	if (chdir(dest) < 0) {
+		INTON;
+		return (-1);
+	}
+	p = findcwd(NULL);
+	if (p == NULL) {
+		warning("warning: failed to get name of current directory");
+		rc = 1;
+	}
+	updatepwd(p);
+	INTON;
+	return (rc);
+}
+
+/*
+ * Get the next component of the path name pointed to by cdcomppath.
+ * This routine overwrites the string pointed to by cdcomppath.
+ */
+static char *
+getcomponent(void)
+{
+	char *p;
+	char *start;
+
+	if ((p = cdcomppath) == NULL)
+		return NULL;
+	start = cdcomppath;
+	while (*p != '/' && *p != '\0')
+		p++;
+	if (*p == '\0') {
+		cdcomppath = NULL;
+	} else {
+		*p++ = '\0';
+		cdcomppath = p;
+	}
+	return start;
+}
+
+
+static char *
+findcwd(char *dir)
+{
+	char *new;
+	char *p;
+
+	/*
+	 * If our argument is NULL, we don't know the current directory
+	 * any more because we traversed a symbolic link or something
+	 * we couldn't stat().
+	 */
+	if (dir == NULL || curdir == NULL)
+		return getpwd2();
+	cdcomppath = stsavestr(dir);
+	STARTSTACKSTR(new);
+	if (*dir != '/') {
+		STPUTS(curdir, new);
+		if (STTOPC(new) == '/')
+			STUNPUTC(new);
+	}
+	while ((p = getcomponent()) != NULL) {
+		if (equal(p, "..")) {
+			while (new > stackblock() && (STUNPUTC(new), *new) != '/');
+		} else if (*p != '\0' && ! equal(p, ".")) {
+			STPUTC('/', new);
+			STPUTS(p, new);
+		}
+	}
+	if (new == stackblock())
+		STPUTC('/', new);
+	STACKSTRNUL(new);
+	return stackblock();
+}
+
+/*
+ * Update curdir (the name of the current directory) in response to a
+ * cd command.  We also call hashcd to let the routines in exec.c know
+ * that the current directory has changed.
+ */
+static void
+updatepwd(char *dir)
+{
+	hashcd();				/* update command hash table */
+
+	if (prevdir)
+		ckfree(prevdir);
+	prevdir = curdir;
+	curdir = dir ? savestr(dir) : NULL;
+	setvar("PWD", curdir, VEXPORT);
+	setvar("OLDPWD", prevdir, VEXPORT);
+}
+
+int
+pwdcmd(int argc __unused, char **argv __unused)
+{
+	char *p;
+	int ch, phys;
+
+	phys = Pflag;
+	while ((ch = nextopt("LP")) != '\0') {
+		switch (ch) {
+		case 'L':
+			phys = 0;
+			break;
+		case 'P':
+			phys = 1;
+			break;
+		}
+	}
+
+	if (*argptr != NULL)
+		error("too many arguments");
+
+	if (!phys && getpwd()) {
+		out1str(curdir);
+		out1c('\n');
+	} else {
+		if ((p = getpwd2()) == NULL)
+			error(".: %s", strerror(errno));
+		out1str(p);
+		out1c('\n');
+	}
+
+	return 0;
+}
+
+/*
+ * Get the current directory and cache the result in curdir.
+ */
+static char *
+getpwd(void)
+{
+	char *p;
+
+	if (curdir)
+		return curdir;
+
+	p = getpwd2();
+	if (p != NULL)
+		curdir = savestr(p);
+
+	return curdir;
+}
+
+#define MAXPWD 256
+
+/*
+ * Return the current directory.
+ */
+static char *
+getpwd2(void)
+{
+	char *pwd;
+	int i;
+
+	for (i = MAXPWD;; i *= 2) {
+		pwd = stalloc(i);
+		if (getcwd(pwd, i) != NULL)
+			return pwd;
+		stunalloc(pwd);
+		if (errno != ERANGE)
+			break;
+	}
+
+	return NULL;
+}
+
+/*
+ * Initialize PWD in a new shell.
+ * If the shell is interactive, we need to warn if this fails.
+ */
+void
+pwd_init(int warn)
+{
+	char *pwd;
+	struct stat stdot, stpwd;
+
+	pwd = lookupvar("PWD");
+	if (pwd && *pwd == '/' && stat(".", &stdot) != -1 &&
+	    stat(pwd, &stpwd) != -1 &&
+	    stdot.st_dev == stpwd.st_dev &&
+	    stdot.st_ino == stpwd.st_ino) {
+		if (curdir)
+			ckfree(curdir);
+		curdir = savestr(pwd);
+	}
+	if (getpwd() == NULL && warn)
+		out2fmt_flush("sh: cannot determine working directory\n");
+	setvar("PWD", curdir, VEXPORT);
+}
diff --git a/external/sh/cd.h b/external/sh/cd.h
new file mode 100644
index 00000000..6a2c5d3b
--- /dev/null
+++ b/external/sh/cd.h
@@ -0,0 +1,32 @@
+/*-
+ * Copyright (c) 1995
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD: head/bin/sh/cd.h 223060 2011-06-13 21:03:27Z jilles $
+ */
+
+void	 pwd_init(int);
diff --git a/external/sh/error.c b/external/sh/error.c
new file mode 100644
index 00000000..65198dd2
--- /dev/null
+++ b/external/sh/error.c
@@ -0,0 +1,199 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)error.c	8.2 (Berkeley) 5/4/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: head/bin/sh/error.c 279569 2015-03-03 21:21:43Z jilles $");
+
+/*
+ * Errors and exceptions.
+ */
+
+#include "shell.h"
+#include "eval.h"
+#include "main.h"
+#include "options.h"
+#include "output.h"
+#include "error.h"
+#include "nodes.h" /* show.h needs nodes.h */
+#include "show.h"
+#include "trap.h"
+#include <signal.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+
+
+/*
+ * Code to handle exceptions in C.
+ */
+
+struct jmploc *handler;
+volatile sig_atomic_t exception;
+volatile sig_atomic_t suppressint;
+volatile sig_atomic_t intpending;
+
+
+static void exverror(int, const char *, va_list) __printf0like(2, 0) __dead2;
+
+/*
+ * Called to raise an exception.  Since C doesn't include exceptions, we
+ * just do a longjmp to the exception handler.  The type of exception is
+ * stored in the global variable "exception".
+ *
+ * Interrupts are disabled; they should be reenabled when the exception is
+ * caught.
+ */
+
+void
+exraise(int e)
+{
+	INTOFF;
+	if (handler == NULL)
+		abort();
+	exception = e;
+	longjmp(handler->loc, 1);
+}
+
+
+/*
+ * Called from trap.c when a SIGINT is received and not suppressed, or when
+ * an interrupt is pending and interrupts are re-enabled using INTON.
+ * (If the user specifies that SIGINT is to be trapped or ignored using the
+ * trap builtin, then this routine is not called.)  Suppressint is nonzero
+ * when interrupts are held using the INTOFF macro.  If SIGINTs are not
+ * suppressed and the shell is not a root shell, then we want to be
+ * terminated if we get here, as if we were terminated directly by a SIGINT.
+ * Arrange for this here.
+ */
+
+void
+onint(void)
+{
+	sigset_t sigs;
+
+	intpending = 0;
+	sigemptyset(&sigs);
+	sigprocmask(SIG_SETMASK, &sigs, NULL);
+
+	/*
+	 * This doesn't seem to be needed, since main() emits a newline.
+	 */
+#if 0
+	if (tcgetpgrp(0) == getpid())
+		write(STDERR_FILENO, "\n", 1);
+#endif
+	if (rootshell && iflag)
+		exraise(EXINT);
+	else {
+		signal(SIGINT, SIG_DFL);
+		kill(getpid(), SIGINT);
+		_exit(128 + SIGINT);
+	}
+}
+
+
+static void
+vwarning(const char *msg, va_list ap)
+{
+	if (commandname)
+		outfmt(out2, "%s: ", commandname);
+	else if (arg0)
+		outfmt(out2, "%s: ", arg0);
+	doformat(out2, msg, ap);
+	out2fmt_flush("\n");
+}
+
+
+void
+warning(const char *msg, ...)
+{
+	va_list ap;
+	va_start(ap, msg);
+	vwarning(msg, ap);
+	va_end(ap);
+}
+
+
+/*
+ * Exverror is called to raise the error exception.  If the first argument
+ * is not NULL then error prints an error message using printf style
+ * formatting.  It then raises the error exception.
+ */
+static void
+exverror(int cond, const char *msg, va_list ap)
+{
+	/*
+	 * An interrupt trumps an error.  Certain places catch error
+	 * exceptions or transform them to a plain nonzero exit code
+	 * in child processes, and if an error exception can be handled,
+	 * an interrupt can be handled as well.
+	 *
+	 * exraise() will disable interrupts for the exception handler.
+	 */
+	FORCEINTON;
+
+#ifdef DEBUG
+	if (msg)
+		TRACE(("exverror(%d, \"%s\") pid=%d\n", cond, msg, getpid()));
+	else
+		TRACE(("exverror(%d, NULL) pid=%d\n", cond, getpid()));
+#endif
+	if (msg)
+		vwarning(msg, ap);
+	flushall();
+	exraise(cond);
+}
+
+
+void
+error(const char *msg, ...)
+{
+	va_list ap;
+	va_start(ap, msg);
+	exverror(EXERROR, msg, ap);
+	va_end(ap);
+}
+
+
+void
+exerror(int cond, const char *msg, ...)
+{
+	va_list ap;
+	va_start(ap, msg);
+	exverror(cond, msg, ap);
+	va_end(ap);
+}
diff --git a/external/sh/error.h b/external/sh/error.h
new file mode 100644
index 00000000..4aa7f370
--- /dev/null
+++ b/external/sh/error.h
@@ -0,0 +1,95 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)error.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: head/bin/sh/error.h 276038 2014-12-21 23:09:59Z jilles $
+ */
+
+/*
+ * We enclose jmp_buf in a structure so that we can declare pointers to
+ * jump locations.  The global variable handler contains the location to
+ * jump to when an exception occurs, and the global variable exception
+ * contains a code identifying the exception.  To implement nested
+ * exception handlers, the user should save the value of handler on entry
+ * to an inner scope, set handler to point to a jmploc structure for the
+ * inner scope, and restore handler on exit from the scope.
+ */
+
+#include <setjmp.h>
+#include <signal.h>
+
+struct jmploc {
+	jmp_buf loc;
+};
+
+extern struct jmploc *handler;
+extern volatile sig_atomic_t exception;
+
+/* exceptions */
+#define EXINT 0		/* SIGINT received */
+#define EXERROR 1	/* a generic error */
+#define EXEXEC 2	/* command execution failed */
+#define EXEXIT 3	/* call exitshell(exitstatus) */
+
+
+/*
+ * These macros allow the user to suspend the handling of interrupt signals
+ * over a period of time.  This is similar to SIGHOLD to or sigblock, but
+ * much more efficient and portable.  (But hacking the kernel is so much
+ * more fun than worrying about efficiency and portability. :-))
+ */
+
+extern volatile sig_atomic_t suppressint;
+extern volatile sig_atomic_t intpending;
+
+#define INTOFF suppressint++
+#define INTON { if (--suppressint == 0 && intpending) onint(); }
+#define is_int_on() suppressint
+#define SETINTON(s) suppressint = (s)
+#define FORCEINTON {suppressint = 0; if (intpending) onint();}
+#define SET_PENDING_INT intpending = 1
+#define CLEAR_PENDING_INT intpending = 0
+#define int_pending() intpending
+
+void exraise(int) __dead2;
+void onint(void) __dead2;
+void warning(const char *, ...) __printflike(1, 2);
+void error(const char *, ...) __printf0like(1, 2) __dead2;
+void exerror(int, const char *, ...) __printf0like(2, 3) __dead2;
+
+
+/*
+ * BSD setjmp saves the signal mask, which violates ANSI C and takes time,
+ * so we use _setjmp instead.
+ */
+
+#define setjmp(jmploc)	_setjmp(jmploc)
+#define longjmp(jmploc, val)	_longjmp(jmploc, val)
diff --git a/external/sh/eval.c b/external/sh/eval.c
new file mode 100644
index 00000000..d66cdb58
--- /dev/null
+++ b/external/sh/eval.c
@@ -0,0 +1,1382 @@
+/*-
+ * Copyright (c) 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)eval.c	8.9 (Berkeley) 6/8/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: head/bin/sh/eval.c 279508 2015-03-01 22:32:23Z jilles $");
+
+#include <paths.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/resource.h>
+#include <sys/wait.h> /* For WIFSIGNALED(status) */
+#include <errno.h>
+
+/*
+ * Evaluate a command.
+ */
+
+#include "shell.h"
+#include "nodes.h"
+#include "syntax.h"
+#include "expand.h"
+#include "parser.h"
+#include "jobs.h"
+#include "eval.h"
+#include "builtins.h"
+#include "options.h"
+#include "exec.h"
+#include "redir.h"
+#include "input.h"
+#include "output.h"
+#include "trap.h"
+#include "var.h"
+#include "memalloc.h"
+#include "error.h"
+#include "show.h"
+#include "mystring.h"
+#ifndef NO_HISTORY
+#include "myhistedit.h"
+#endif
+
+
+int evalskip;			/* set if we are skipping commands */
+int skipcount;			/* number of levels to skip */
+static int loopnest;		/* current loop nesting level */
+int funcnest;			/* depth of function calls */
+static int builtin_flags;	/* evalcommand flags for builtins */
+
+
+char *commandname;
+struct strlist *cmdenviron;
+int exitstatus;			/* exit status of last command */
+int oexitstatus;		/* saved exit status */
+
+
+static void evalloop(union node *, int);
+static void evalfor(union node *, int);
+static union node *evalcase(union node *);
+static void evalsubshell(union node *, int);
+static void evalredir(union node *, int);
+static void exphere(union node *, struct arglist *);
+static void expredir(union node *);
+static void evalpipe(union node *);
+static int is_valid_fast_cmdsubst(union node *n);
+static void evalcommand(union node *, int, struct backcmd *);
+static void prehash(union node *);
+
+
+/*
+ * Called to reset things after an exception.
+ */
+
+void
+reseteval(void)
+{
+	evalskip = 0;
+	loopnest = 0;
+}
+
+
+/*
+ * The eval command.
+ */
+
+int
+evalcmd(int argc, char **argv)
+{
+        char *p;
+        char *concat;
+        char **ap;
+
+        if (argc > 1) {
+                p = argv[1];
+                if (argc > 2) {
+                        STARTSTACKSTR(concat);
+                        ap = argv + 2;
+                        for (;;) {
+                                STPUTS(p, concat);
+                                if ((p = *ap++) == NULL)
+                                        break;
+                                STPUTC(' ', concat);
+                        }
+                        STPUTC('\0', concat);
+                        p = grabstackstr(concat);
+                }
+                evalstring(p, builtin_flags);
+        } else
+                exitstatus = 0;
+        return exitstatus;
+}
+
+
+/*
+ * Execute a command or commands contained in a string.
+ */
+
+void
+evalstring(const char *s, int flags)
+{
+	union node *n;
+	struct stackmark smark;
+	int flags_exit;
+	int any;
+
+	flags_exit = flags & EV_EXIT;
+	flags &= ~EV_EXIT;
+	any = 0;
+	setstackmark(&smark);
+	setinputstring(s, 1);
+	while ((n = parsecmd(0)) != NEOF) {
+		if (n != NULL && !nflag) {
+			if (flags_exit && preadateof())
+				evaltree(n, flags | EV_EXIT);
+			else
+				evaltree(n, flags);
+			any = 1;
+			if (evalskip)
+				break;
+		}
+		popstackmark(&smark);
+		setstackmark(&smark);
+	}
+	popfile();
+	popstackmark(&smark);
+	if (!any)
+		exitstatus = 0;
+	if (flags_exit)
+		exraise(EXEXIT);
+}
+
+
+/*
+ * Evaluate a parse tree.  The value is left in the global variable
+ * exitstatus.
+ */
+
+void
+evaltree(union node *n, int flags)
+{
+	int do_etest;
+	union node *next;
+	struct stackmark smark;
+
+	setstackmark(&smark);
+	do_etest = 0;
+	if (n == NULL) {
+		TRACE(("evaltree(NULL) called\n"));
+		exitstatus = 0;
+		goto out;
+	}
+	do {
+		next = NULL;
+#ifndef NO_HISTORY
+		displayhist = 1;	/* show history substitutions done with fc */
+#endif
+		TRACE(("evaltree(%p: %d) called\n", (void *)n, n->type));
+		switch (n->type) {
+		case NSEMI:
+			evaltree(n->nbinary.ch1, flags & ~EV_EXIT);
+			if (evalskip)
+				goto out;
+			next = n->nbinary.ch2;
+			break;
+		case NAND:
+			evaltree(n->nbinary.ch1, EV_TESTED);
+			if (evalskip || exitstatus != 0) {
+				goto out;
+			}
+			next = n->nbinary.ch2;
+			break;
+		case NOR:
+			evaltree(n->nbinary.ch1, EV_TESTED);
+			if (evalskip || exitstatus == 0)
+				goto out;
+			next = n->nbinary.ch2;
+			break;
+		case NREDIR:
+			evalredir(n, flags);
+			break;
+		case NSUBSHELL:
+			evalsubshell(n, flags);
+			do_etest = !(flags & EV_TESTED);
+			break;
+		case NBACKGND:
+			evalsubshell(n, flags);
+			break;
+		case NIF: {
+			evaltree(n->nif.test, EV_TESTED);
+			if (evalskip)
+				goto out;
+			if (exitstatus == 0)
+				next = n->nif.ifpart;
+			else if (n->nif.elsepart)
+				next = n->nif.elsepart;
+			else
+				exitstatus = 0;
+			break;
+		}
+		case NWHILE:
+		case NUNTIL:
+			evalloop(n, flags & ~EV_EXIT);
+			break;
+		case NFOR:
+			evalfor(n, flags & ~EV_EXIT);
+			break;
+		case NCASE:
+			next = evalcase(n);
+			break;
+		case NCLIST:
+			next = n->nclist.body;
+			break;
+		case NCLISTFALLTHRU:
+			if (n->nclist.body) {
+				evaltree(n->nclist.body, flags & ~EV_EXIT);
+				if (evalskip)
+					goto out;
+			}
+			next = n->nclist.next;
+			break;
+		case NDEFUN:
+			defun(n->narg.text, n->narg.next);
+			exitstatus = 0;
+			break;
+		case NNOT:
+			evaltree(n->nnot.com, EV_TESTED);
+			if (evalskip)
+				goto out;
+			exitstatus = !exitstatus;
+			break;
+
+		case NPIPE:
+			evalpipe(n);
+			do_etest = !(flags & EV_TESTED);
+			break;
+		case NCMD:
+			evalcommand(n, flags, (struct backcmd *)NULL);
+			do_etest = !(flags & EV_TESTED);
+			break;
+		default:
+			out1fmt("Node type = %d\n", n->type);
+			flushout(&output);
+			break;
+		}
+		n = next;
+		popstackmark(&smark);
+		setstackmark(&smark);
+	} while (n != NULL);
+out:
+	popstackmark(&smark);
+	if (pendingsig)
+		dotrap();
+	if (eflag && exitstatus != 0 && do_etest)
+		exitshell(exitstatus);
+	if (flags & EV_EXIT)
+		exraise(EXEXIT);
+}
+
+
+static void
+evalloop(union node *n, int flags)
+{
+	int status;
+
+	loopnest++;
+	status = 0;
+	for (;;) {
+		if (!evalskip)
+			evaltree(n->nbinary.ch1, EV_TESTED);
+		if (evalskip) {
+			if (evalskip == SKIPCONT && --skipcount <= 0) {
+				evalskip = 0;
+				continue;
+			}
+			if (evalskip == SKIPBREAK && --skipcount <= 0)
+				evalskip = 0;
+			if (evalskip == SKIPRETURN)
+				status = exitstatus;
+			break;
+		}
+		if (n->type == NWHILE) {
+			if (exitstatus != 0)
+				break;
+		} else {
+			if (exitstatus == 0)
+				break;
+		}
+		evaltree(n->nbinary.ch2, flags);
+		status = exitstatus;
+	}
+	loopnest--;
+	exitstatus = status;
+}
+
+
+
+static void
+evalfor(union node *n, int flags)
+{
+	struct arglist arglist;
+	union node *argp;
+	struct strlist *sp;
+	int status;
+
+	arglist.lastp = &arglist.list;
+	for (argp = n->nfor.args ; argp ; argp = argp->narg.next) {
+		oexitstatus = exitstatus;
+		expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
+	}
+	*arglist.lastp = NULL;
+
+	loopnest++;
+	status = 0;
+	for (sp = arglist.list ; sp ; sp = sp->next) {
+		setvar(n->nfor.var, sp->text, 0);
+		evaltree(n->nfor.body, flags);
+		status = exitstatus;
+		if (evalskip) {
+			if (evalskip == SKIPCONT && --skipcount <= 0) {
+				evalskip = 0;
+				continue;
+			}
+			if (evalskip == SKIPBREAK && --skipcount <= 0)
+				evalskip = 0;
+			break;
+		}
+	}
+	loopnest--;
+	exitstatus = status;
+}
+
+
+/*
+ * Evaluate a case statement, returning the selected tree.
+ *
+ * The exit status needs care to get right.
+ */
+
+static union node *
+evalcase(union node *n)
+{
+	union node *cp;
+	union node *patp;
+	struct arglist arglist;
+
+	arglist.lastp = &arglist.list;
+	oexitstatus = exitstatus;
+	expandarg(n->ncase.expr, &arglist, EXP_TILDE);
+	for (cp = n->ncase.cases ; cp ; cp = cp->nclist.next) {
+		for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) {
+			if (casematch(patp, arglist.list->text)) {
+				while (cp->nclist.next &&
+				    cp->type == NCLISTFALLTHRU &&
+				    cp->nclist.body == NULL)
+					cp = cp->nclist.next;
+				if (cp->nclist.next &&
+				    cp->type == NCLISTFALLTHRU)
+					return (cp);
+				if (cp->nclist.body == NULL)
+					exitstatus = 0;
+				return (cp->nclist.body);
+			}
+		}
+	}
+	exitstatus = 0;
+	return (NULL);
+}
+
+
+
+/*
+ * Kick off a subshell to evaluate a tree.
+ */
+
+static void
+evalsubshell(union node *n, int flags)
+{
+	struct job *jp;
+	int backgnd = (n->type == NBACKGND);
+
+	oexitstatus = exitstatus;
+	expredir(n->nredir.redirect);
+	if ((!backgnd && flags & EV_EXIT && !have_traps()) ||
+			forkshell(jp = makejob(n, 1), n, backgnd) == 0) {
+		if (backgnd)
+			flags &=~ EV_TESTED;
+		redirect(n->nredir.redirect, 0);
+		evaltree(n->nredir.n, flags | EV_EXIT);	/* never returns */
+	} else if (! backgnd) {
+		INTOFF;
+		exitstatus = waitforjob(jp, (int *)NULL);
+		INTON;
+	} else
+		exitstatus = 0;
+}
+
+
+/*
+ * Evaluate a redirected compound command.
+ */
+
+static void
+evalredir(union node *n, int flags)
+{
+	struct jmploc jmploc;
+	struct jmploc *savehandler;
+	volatile int in_redirect = 1;
+
+	oexitstatus = exitstatus;
+	expredir(n->nredir.redirect);
+	savehandler = handler;
+	if (setjmp(jmploc.loc)) {
+		int e;
+
+		handler = savehandler;
+		e = exception;
+		popredir();
+		if (e == EXERROR || e == EXEXEC) {
+			if (in_redirect) {
+				exitstatus = 2;
+				return;
+			}
+		}
+		longjmp(handler->loc, 1);
+	} else {
+		INTOFF;
+		handler = &jmploc;
+		redirect(n->nredir.redirect, REDIR_PUSH);
+		in_redirect = 0;
+		INTON;
+		evaltree(n->nredir.n, flags);
+	}
+	INTOFF;
+	handler = savehandler;
+	popredir();
+	INTON;
+}
+
+
+static void
+exphere(union node *redir, struct arglist *fn)
+{
+	struct jmploc jmploc;
+	struct jmploc *savehandler;
+	struct localvar *savelocalvars;
+	int need_longjmp = 0;
+
+	redir->nhere.expdoc = "";
+	savelocalvars = localvars;
+	localvars = NULL;
+	forcelocal++;
+	savehandler = handler;
+	if (setjmp(jmploc.loc))
+		need_longjmp = exception != EXERROR && exception != EXEXEC;
+	else {
+		handler = &jmploc;
+		expandarg(redir->nhere.doc, fn, 0);
+		redir->nhere.expdoc = fn->list->text;
+		INTOFF;
+	}
+	handler = savehandler;
+	forcelocal--;
+	poplocalvars();
+	localvars = savelocalvars;
+	if (need_longjmp)
+		longjmp(handler->loc, 1);
+	INTON;
+}
+
+
+/*
+ * Compute the names of the files in a redirection list.
+ */
+
+static void
+expredir(union node *n)
+{
+	union node *redir;
+
+	for (redir = n ; redir ; redir = redir->nfile.next) {
+		struct arglist fn;
+		fn.lastp = &fn.list;
+		switch (redir->type) {
+		case NFROM:
+		case NTO:
+		case NFROMTO:
+		case NAPPEND:
+		case NCLOBBER:
+			expandarg(redir->nfile.fname, &fn, EXP_TILDE);
+			redir->nfile.expfname = fn.list->text;
+			break;
+		case NFROMFD:
+		case NTOFD:
+			if (redir->ndup.vname) {
+				expandarg(redir->ndup.vname, &fn, EXP_TILDE);
+				fixredir(redir, fn.list->text, 1);
+			}
+			break;
+		case NXHERE:
+			exphere(redir, &fn);
+			break;
+		}
+	}
+}
+
+
+
+/*
+ * Evaluate a pipeline.  All the processes in the pipeline are children
+ * of the process creating the pipeline.  (This differs from some versions
+ * of the shell, which make the last process in a pipeline the parent
+ * of all the rest.)
+ */
+
+static void
+evalpipe(union node *n)
+{
+	struct job *jp;
+	struct nodelist *lp;
+	int pipelen;
+	int prevfd;
+	int pip[2];
+
+	TRACE(("evalpipe(%p) called\n", (void *)n));
+	pipelen = 0;
+	for (lp = n->npipe.cmdlist ; lp ; lp = lp->next)
+		pipelen++;
+	INTOFF;
+	jp = makejob(n, pipelen);
+	prevfd = -1;
+	for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
+		prehash(lp->n);
+		pip[1] = -1;
+		if (lp->next) {
+			if (pipe(pip) < 0) {
+				if (prevfd >= 0)
+					close(prevfd);
+				error("Pipe call failed: %s", strerror(errno));
+			}
+		}
+		if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) {
+			INTON;
+			if (prevfd > 0) {
+				dup2(prevfd, 0);
+				close(prevfd);
+			}
+			if (pip[1] >= 0) {
+				if (!(prevfd >= 0 && pip[0] == 0))
+					close(pip[0]);
+				if (pip[1] != 1) {
+					dup2(pip[1], 1);
+					close(pip[1]);
+				}
+			}
+			evaltree(lp->n, EV_EXIT);
+		}
+		if (prevfd >= 0)
+			close(prevfd);
+		prevfd = pip[0];
+		if (pip[1] != -1)
+			close(pip[1]);
+	}
+	INTON;
+	if (n->npipe.backgnd == 0) {
+		INTOFF;
+		exitstatus = waitforjob(jp, (int *)NULL);
+		TRACE(("evalpipe:  job done exit status %d\n", exitstatus));
+		INTON;
+	} else
+		exitstatus = 0;
+}
+
+
+
+static int
+is_valid_fast_cmdsubst(union node *n)
+{
+
+	return (n->type == NCMD);
+}
+
+/*
+ * Execute a command inside back quotes.  If it's a builtin command, we
+ * want to save its output in a block obtained from malloc.  Otherwise
+ * we fork off a subprocess and get the output of the command via a pipe.
+ * Should be called with interrupts off.
+ */
+
+void
+evalbackcmd(union node *n, struct backcmd *result)
+{
+	int pip[2];
+	struct job *jp;
+	struct stackmark smark;
+	struct jmploc jmploc;
+	struct jmploc *savehandler;
+	struct localvar *savelocalvars;
+
+	result->fd = -1;
+	result->buf = NULL;
+	result->nleft = 0;
+	result->jp = NULL;
+	if (n == NULL) {
+		exitstatus = 0;
+		return;
+	}
+	setstackmark(&smark);
+	exitstatus = oexitstatus;
+	if (is_valid_fast_cmdsubst(n)) {
+		savelocalvars = localvars;
+		localvars = NULL;
+		forcelocal++;
+		savehandler = handler;
+		if (setjmp(jmploc.loc)) {
+			if (exception == EXERROR || exception == EXEXEC)
+				exitstatus = 2;
+			else if (exception != 0) {
+				handler = savehandler;
+				forcelocal--;
+				poplocalvars();
+				localvars = savelocalvars;
+				longjmp(handler->loc, 1);
+			}
+		} else {
+			handler = &jmploc;
+			evalcommand(n, EV_BACKCMD, result);
+		}
+		handler = savehandler;
+		forcelocal--;
+		poplocalvars();
+		localvars = savelocalvars;
+	} else {
+		if (pipe(pip) < 0)
+			error("Pipe call failed: %s", strerror(errno));
+		jp = makejob(n, 1);
+		if (forkshell(jp, n, FORK_NOJOB) == 0) {
+			FORCEINTON;
+			close(pip[0]);
+			if (pip[1] != 1) {
+				dup2(pip[1], 1);
+				close(pip[1]);
+			}
+			evaltree(n, EV_EXIT);
+		}
+		close(pip[1]);
+		result->fd = pip[0];
+		result->jp = jp;
+	}
+	popstackmark(&smark);
+	TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n",
+		result->fd, result->buf, result->nleft, result->jp));
+}
+
+static int
+mustexpandto(const char *argtext, const char *mask)
+{
+	for (;;) {
+		if (*argtext == CTLQUOTEMARK || *argtext == CTLQUOTEEND) {
+			argtext++;
+			continue;
+		}
+		if (*argtext == CTLESC)
+			argtext++;
+		else if (BASESYNTAX[(int)*argtext] == CCTL)
+			return (0);
+		if (*argtext != *mask)
+			return (0);
+		if (*argtext == '\0')
+			return (1);
+		argtext++;
+		mask++;
+	}
+}
+
+static int
+isdeclarationcmd(struct narg *arg)
+{
+	int have_command = 0;
+
+	if (arg == NULL)
+		return (0);
+	while (mustexpandto(arg->text, "command")) {
+		have_command = 1;
+		arg = &arg->next->narg;
+		if (arg == NULL)
+			return (0);
+		/*
+		 * To also allow "command -p" and "command --" as part of
+		 * a declaration command, add code here.
+		 * We do not do this, as ksh does not do it either and it
+		 * is not required by POSIX.
+		 */
+	}
+	return (mustexpandto(arg->text, "export") ||
+	    mustexpandto(arg->text, "readonly") ||
+	    (mustexpandto(arg->text, "local") &&
+		(have_command || !isfunc("local"))));
+}
+
+static void
+xtracecommand(struct arglist *varlist, struct arglist *arglist)
+{
+	struct strlist *sp;
+	char sep = 0;
+	const char *p, *ps4;
+
+	ps4 = expandstr(ps4val());
+	out2str(ps4 != NULL ? ps4 : ps4val());
+	for (sp = varlist->list ; sp ; sp = sp->next) {
+		if (sep != 0)
+			out2c(' ');
+		p = strchr(sp->text, '=');
+		if (p != NULL) {
+			p++;
+			outbin(sp->text, p - sp->text, out2);
+			out2qstr(p);
+		} else
+			out2qstr(sp->text);
+		sep = ' ';
+	}
+	for (sp = arglist->list ; sp ; sp = sp->next) {
+		if (sep != 0)
+			out2c(' ');
+		out2qstr(sp->text);
+		sep = ' ';
+	}
+	out2c('\n');
+	flushout(&errout);
+}
+
+/*
+ * Check if a builtin can safely be executed in the same process,
+ * even though it should be in a subshell (command substitution).
+ * Note that jobid, jobs, times and trap can show information not
+ * available in a child process; this is deliberate.
+ * The arguments should already have been expanded.
+ */
+static int
+safe_builtin(int idx, int argc, char **argv)
+{
+	if (idx == BLTINCMD || idx == COMMANDCMD || idx == ECHOCMD ||
+	    idx == FALSECMD || idx == JOBIDCMD || idx == JOBSCMD ||
+	    idx == KILLCMD || idx == PRINTFCMD || idx == PWDCMD ||
+	    idx == TESTCMD || idx == TIMESCMD || idx == TRUECMD ||
+	    idx == TYPECMD)
+		return (1);
+	if (idx == EXPORTCMD || idx == TRAPCMD || idx == ULIMITCMD ||
+	    idx == UMASKCMD)
+		return (argc <= 1 || (argc == 2 && argv[1][0] == '-'));
+	if (idx == SETCMD)
+		return (argc <= 1 || (argc == 2 && (argv[1][0] == '-' ||
+		    argv[1][0] == '+') && argv[1][1] == 'o' &&
+		    argv[1][2] == '\0'));
+	return (0);
+}
+
+/*
+ * Execute a simple command.
+ * Note: This may or may not return if (flags & EV_EXIT).
+ */
+
+static void
+evalcommand(union node *cmd, int flags, struct backcmd *backcmd)
+{
+	union node *argp;
+	struct arglist arglist;
+	struct arglist varlist;
+	char **argv;
+	int argc;
+	char **envp;
+	int varflag;
+	struct strlist *sp;
+	int mode;
+	int pip[2];
+	struct cmdentry cmdentry;
+	struct job *jp;
+	struct jmploc jmploc;
+	struct jmploc *savehandler;
+	char *savecmdname;
+	struct shparam saveparam;
+	struct localvar *savelocalvars;
+	struct parsefile *savetopfile;
+	volatile int e;
+	char *lastarg;
+	int realstatus;
+	int do_clearcmdentry;
+	const char *path = pathval();
+
+	/* First expand the arguments. */
+	TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags));
+	arglist.lastp = &arglist.list;
+	varlist.lastp = &varlist.list;
+	varflag = 1;
+	jp = NULL;
+	do_clearcmdentry = 0;
+	oexitstatus = exitstatus;
+	exitstatus = 0;
+	for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) {
+		if (varflag && isassignment(argp->narg.text)) {
+			expandarg(argp, varflag == 1 ? &varlist : &arglist,
+			    EXP_VARTILDE);
+			continue;
+		} else if (varflag == 1)
+			varflag = isdeclarationcmd(&argp->narg) ? 2 : 0;
+		expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
+	}
+	*arglist.lastp = NULL;
+	*varlist.lastp = NULL;
+	expredir(cmd->ncmd.redirect);
+	argc = 0;
+	for (sp = arglist.list ; sp ; sp = sp->next)
+		argc++;
+	/* Add one slot at the beginning for tryexec(). */
+	argv = stalloc(sizeof (char *) * (argc + 2));
+	argv++;
+
+	for (sp = arglist.list ; sp ; sp = sp->next) {
+		TRACE(("evalcommand arg: %s\n", sp->text));
+		*argv++ = sp->text;
+	}
+	*argv = NULL;
+	lastarg = NULL;
+	if (iflag && funcnest == 0 && argc > 0)
+		lastarg = argv[-1];
+	argv -= argc;
+
+	/* Print the command if xflag is set. */
+	if (xflag)
+		xtracecommand(&varlist, &arglist);
+
+	/* Now locate the command. */
+	if (argc == 0) {
+		/* Variable assignment(s) without command */
+		cmdentry.cmdtype = CMDBUILTIN;
+		cmdentry.u.index = BLTINCMD;
+		cmdentry.special = 0;
+	} else {
+		static const char PATH[] = "PATH=";
+		int cmd_flags = 0, bltinonly = 0;
+
+		/*
+		 * Modify the command lookup path, if a PATH= assignment
+		 * is present
+		 */
+		for (sp = varlist.list ; sp ; sp = sp->next)
+			if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) {
+				path = sp->text + sizeof(PATH) - 1;
+				/*
+				 * On `PATH=... command`, we need to make
+				 * sure that the command isn't using the
+				 * non-updated hash table of the outer PATH
+				 * setting and we need to make sure that
+				 * the hash table isn't filled with items
+				 * from the temporary setting.
+				 *
+				 * It would be better to forbit using and
+				 * updating the table while this command
+				 * runs, by the command finding mechanism
+				 * is heavily integrated with hash handling,
+				 * so we just delete the hash before and after
+				 * the command runs. Partly deleting like
+				 * changepatch() does doesn't seem worth the
+				 * bookinging effort, since most such runs add
+				 * directories in front of the new PATH.
+				 */
+				clearcmdentry();
+				do_clearcmdentry = 1;
+			}
+
+		for (;;) {
+			if (bltinonly) {
+				cmdentry.u.index = find_builtin(*argv, &cmdentry.special);
+				if (cmdentry.u.index < 0) {
+					cmdentry.u.index = BLTINCMD;
+					argv--;
+					argc++;
+					break;
+				}
+			} else
+				find_command(argv[0], &cmdentry, cmd_flags, path);
+			/* implement the bltin and command builtins here */
+			if (cmdentry.cmdtype != CMDBUILTIN)
+				break;
+			if (cmdentry.u.index == BLTINCMD) {
+				if (argc == 1)
+					break;
+				argv++;
+				argc--;
+				bltinonly = 1;
+			} else if (cmdentry.u.index == COMMANDCMD) {
+				if (argc == 1)
+					break;
+				if (!strcmp(argv[1], "-p")) {
+					if (argc == 2)
+						break;
+					if (argv[2][0] == '-') {
+						if (strcmp(argv[2], "--"))
+							break;
+						if (argc == 3)
+							break;
+						argv += 3;
+						argc -= 3;
+					} else {
+						argv += 2;
+						argc -= 2;
+					}
+					path = _PATH_STDPATH;
+					clearcmdentry();
+					do_clearcmdentry = 1;
+				} else if (!strcmp(argv[1], "--")) {
+					if (argc == 2)
+						break;
+					argv += 2;
+					argc -= 2;
+				} else if (argv[1][0] == '-')
+					break;
+				else {
+					argv++;
+					argc--;
+				}
+				cmd_flags |= DO_NOFUNC;
+				bltinonly = 0;
+			} else
+				break;
+		}
+		/*
+		 * Special builtins lose their special properties when
+		 * called via 'command'.
+		 */
+		if (cmd_flags & DO_NOFUNC)
+			cmdentry.special = 0;
+	}
+
+	/* Fork off a child process if necessary. */
+	if (((cmdentry.cmdtype == CMDNORMAL || cmdentry.cmdtype == CMDUNKNOWN)
+	    && ((flags & EV_EXIT) == 0 || have_traps()))
+	 || ((flags & EV_BACKCMD) != 0
+	    && (cmdentry.cmdtype != CMDBUILTIN ||
+		 !safe_builtin(cmdentry.u.index, argc, argv)))) {
+		jp = makejob(cmd, 1);
+		mode = FORK_FG;
+		if (flags & EV_BACKCMD) {
+			mode = FORK_NOJOB;
+			if (pipe(pip) < 0)
+				error("Pipe call failed: %s", strerror(errno));
+		}
+		if (cmdentry.cmdtype == CMDNORMAL &&
+		    cmd->ncmd.redirect == NULL &&
+		    varlist.list == NULL &&
+		    (mode == FORK_FG || mode == FORK_NOJOB) &&
+		    !disvforkset() && !iflag && !mflag) {
+			vforkexecshell(jp, argv, environment(), path,
+			    cmdentry.u.index, flags & EV_BACKCMD ? pip : NULL);
+			goto parent;
+		}
+		if (forkshell(jp, cmd, mode) != 0)
+			goto parent;	/* at end of routine */
+		if (flags & EV_BACKCMD) {
+			FORCEINTON;
+			close(pip[0]);
+			if (pip[1] != 1) {
+				dup2(pip[1], 1);
+				close(pip[1]);
+			}
+			flags &= ~EV_BACKCMD;
+		}
+		flags |= EV_EXIT;
+	}
+
+	/* This is the child process if a fork occurred. */
+	/* Execute the command. */
+	if (cmdentry.cmdtype == CMDFUNCTION) {
+#ifdef DEBUG
+		trputs("Shell function:  ");  trargs(argv);
+#endif
+		saveparam = shellparam;
+		shellparam.malloc = 0;
+		shellparam.reset = 1;
+		shellparam.nparam = argc - 1;
+		shellparam.p = argv + 1;
+		shellparam.optp = NULL;
+		shellparam.optnext = NULL;
+		INTOFF;
+		savelocalvars = localvars;
+		localvars = NULL;
+		reffunc(cmdentry.u.func);
+		savehandler = handler;
+		if (setjmp(jmploc.loc)) {
+			freeparam(&shellparam);
+			shellparam = saveparam;
+			popredir();
+			unreffunc(cmdentry.u.func);
+			poplocalvars();
+			localvars = savelocalvars;
+			funcnest--;
+			handler = savehandler;
+			longjmp(handler->loc, 1);
+		}
+		handler = &jmploc;
+		funcnest++;
+		redirect(cmd->ncmd.redirect, REDIR_PUSH);
+		INTON;
+		for (sp = varlist.list ; sp ; sp = sp->next)
+			mklocal(sp->text);
+		exitstatus = oexitstatus;
+		evaltree(getfuncnode(cmdentry.u.func),
+		    flags & (EV_TESTED | EV_EXIT));
+		INTOFF;
+		unreffunc(cmdentry.u.func);
+		poplocalvars();
+		localvars = savelocalvars;
+		freeparam(&shellparam);
+		shellparam = saveparam;
+		handler = savehandler;
+		funcnest--;
+		popredir();
+		INTON;
+		if (evalskip == SKIPRETURN) {
+			evalskip = 0;
+			skipcount = 0;
+		}
+		if (jp)
+			exitshell(exitstatus);
+	} else if (cmdentry.cmdtype == CMDBUILTIN) {
+#ifdef DEBUG
+		trputs("builtin command:  ");  trargs(argv);
+#endif
+		mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH;
+		if (flags == EV_BACKCMD) {
+			memout.nleft = 0;
+			memout.nextc = memout.buf;
+			memout.bufsize = 64;
+			mode |= REDIR_BACKQ;
+		}
+		savecmdname = commandname;
+		savetopfile = getcurrentfile();
+		cmdenviron = varlist.list;
+		e = -1;
+		savehandler = handler;
+		if (setjmp(jmploc.loc)) {
+			e = exception;
+			if (e == EXINT)
+				exitstatus = SIGINT+128;
+			else if (e != EXEXIT)
+				exitstatus = 2;
+			goto cmddone;
+		}
+		handler = &jmploc;
+		redirect(cmd->ncmd.redirect, mode);
+		outclearerror(out1);
+		/*
+		 * If there is no command word, redirection errors should
+		 * not be fatal but assignment errors should.
+		 */
+		if (argc == 0)
+			cmdentry.special = 1;
+		listsetvar(cmdenviron, cmdentry.special ? 0 : VNOSET);
+		if (argc > 0)
+			bltinsetlocale();
+		commandname = argv[0];
+		argptr = argv + 1;
+		nextopt_optptr = NULL;		/* initialize nextopt */
+		builtin_flags = flags;
+		exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv);
+		flushall();
+		if (outiserror(out1)) {
+			warning("write error on stdout");
+			if (exitstatus == 0 || exitstatus == 1)
+				exitstatus = 2;
+		}
+cmddone:
+		if (argc > 0)
+			bltinunsetlocale();
+		cmdenviron = NULL;
+		out1 = &output;
+		out2 = &errout;
+		freestdout();
+		handler = savehandler;
+		commandname = savecmdname;
+		if (jp)
+			exitshell(exitstatus);
+		if (flags == EV_BACKCMD) {
+			backcmd->buf = memout.buf;
+			backcmd->nleft = memout.nextc - memout.buf;
+			memout.buf = NULL;
+		}
+		if (cmdentry.u.index != EXECCMD)
+			popredir();
+		if (e != -1) {
+			if ((e != EXERROR && e != EXEXEC)
+			    || cmdentry.special)
+				exraise(e);
+			popfilesupto(savetopfile);
+			if (flags != EV_BACKCMD)
+				FORCEINTON;
+		}
+	} else {
+#ifdef DEBUG
+		trputs("normal command:  ");  trargs(argv);
+#endif
+		redirect(cmd->ncmd.redirect, 0);
+		for (sp = varlist.list ; sp ; sp = sp->next)
+			setvareq(sp->text, VEXPORT|VSTACK);
+		envp = environment();
+		shellexec(argv, envp, path, cmdentry.u.index);
+		/*NOTREACHED*/
+	}
+	goto out;
+
+parent:	/* parent process gets here (if we forked) */
+	if (mode == FORK_FG) {	/* argument to fork */
+		INTOFF;
+		exitstatus = waitforjob(jp, &realstatus);
+		INTON;
+		if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) {
+			evalskip = SKIPBREAK;
+			skipcount = loopnest;
+		}
+	} else if (mode == FORK_NOJOB) {
+		backcmd->fd = pip[0];
+		close(pip[1]);
+		backcmd->jp = jp;
+	}
+
+out:
+	if (lastarg)
+		setvar("_", lastarg, 0);
+	if (do_clearcmdentry)
+		clearcmdentry();
+}
+
+
+
+/*
+ * Search for a command.  This is called before we fork so that the
+ * location of the command will be available in the parent as well as
+ * the child.  The check for "goodname" is an overly conservative
+ * check that the name will not be subject to expansion.
+ */
+
+static void
+prehash(union node *n)
+{
+	struct cmdentry entry;
+
+	if (n && n->type == NCMD && n->ncmd.args)
+		if (goodname(n->ncmd.args->narg.text))
+			find_command(n->ncmd.args->narg.text, &entry, 0,
+				     pathval());
+}
+
+
+
+/*
+ * Builtin commands.  Builtin commands whose functions are closely
+ * tied to evaluation are implemented here.
+ */
+
+/*
+ * No command given, a bltin command with no arguments, or a bltin command
+ * with an invalid name.
+ */
+
+int
+bltincmd(int argc, char **argv)
+{
+	if (argc > 1) {
+		out2fmt_flush("%s: not found\n", argv[1]);
+		return 127;
+	}
+	/*
+	 * Preserve exitstatus of a previous possible redirection
+	 * as POSIX mandates
+	 */
+	return exitstatus;
+}
+
+
+/*
+ * Handle break and continue commands.  Break, continue, and return are
+ * all handled by setting the evalskip flag.  The evaluation routines
+ * above all check this flag, and if it is set they start skipping
+ * commands rather than executing them.  The variable skipcount is
+ * the number of loops to break/continue, or the number of function
+ * levels to return.  (The latter is always 1.)  It should probably
+ * be an error to break out of more loops than exist, but it isn't
+ * in the standard shell so we don't make it one here.
+ */
+
+int
+breakcmd(int argc, char **argv)
+{
+	long n;
+	char *end;
+
+	if (argc > 1) {
+		/* Allow arbitrarily large numbers. */
+		n = strtol(argv[1], &end, 10);
+		if (!is_digit(argv[1][0]) || *end != '\0')
+			error("Illegal number: %s", argv[1]);
+	} else
+		n = 1;
+	if (n > loopnest)
+		n = loopnest;
+	if (n > 0) {
+		evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK;
+		skipcount = n;
+	}
+	return 0;
+}
+
+/*
+ * The `command' command.
+ */
+int
+commandcmd(int argc __unused, char **argv __unused)
+{
+	const char *path;
+	int ch;
+	int cmd = -1;
+
+	path = bltinlookup("PATH", 1);
+
+	while ((ch = nextopt("pvV")) != '\0') {
+		switch (ch) {
+		case 'p':
+			path = _PATH_STDPATH;
+			break;
+		case 'v':
+			cmd = TYPECMD_SMALLV;
+			break;
+		case 'V':
+			cmd = TYPECMD_BIGV;
+			break;
+		}
+	}
+
+	if (cmd != -1) {
+		if (*argptr == NULL || argptr[1] != NULL)
+			error("wrong number of arguments");
+		return typecmd_impl(2, argptr - 1, cmd, path);
+	}
+	if (*argptr != NULL)
+		error("commandcmd bad call");
+
+	/*
+	 * Do nothing successfully if no command was specified;
+	 * ksh also does this.
+	 */
+	return 0;
+}
+
+
+/*
+ * The return command.
+ */
+
+int
+returncmd(int argc, char **argv)
+{
+	int ret = argc > 1 ? number(argv[1]) : oexitstatus;
+
+	evalskip = SKIPRETURN;
+	skipcount = 1;
+	return ret;
+}
+
+
+int
+falsecmd(int argc __unused, char **argv __unused)
+{
+	return 1;
+}
+
+
+int
+truecmd(int argc __unused, char **argv __unused)
+{
+	return 0;
+}
+
+
+int
+execcmd(int argc, char **argv)
+{
+	/*
+	 * Because we have historically not supported any options,
+	 * only treat "--" specially.
+	 */
+	if (argc > 1 && strcmp(argv[1], "--") == 0)
+		argc--, argv++;
+	if (argc > 1) {
+		struct strlist *sp;
+
+		iflag = 0;		/* exit on error */
+		mflag = 0;
+		optschanged();
+		for (sp = cmdenviron; sp ; sp = sp->next)
+			setvareq(sp->text, VEXPORT|VSTACK);
+		shellexec(argv + 1, environment(), pathval(), 0);
+
+	}
+	return 0;
+}
+
+
+int
+timescmd(int argc __unused, char **argv __unused)
+{
+	struct rusage ru;
+	long shumins, shsmins, chumins, chsmins;
+	double shusecs, shssecs, chusecs, chssecs;
+
+	if (getrusage(RUSAGE_SELF, &ru) < 0)
+		return 1;
+	shumins = ru.ru_utime.tv_sec / 60;
+	shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
+	shsmins = ru.ru_stime.tv_sec / 60;
+	shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
+	if (getrusage(RUSAGE_CHILDREN, &ru) < 0)
+		return 1;
+	chumins = ru.ru_utime.tv_sec / 60;
+	chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
+	chsmins = ru.ru_stime.tv_sec / 60;
+	chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
+	out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins,
+	    shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs);
+	return 0;
+}
diff --git a/external/sh/eval.h b/external/sh/eval.h
new file mode 100644
index 00000000..9484b565
--- /dev/null
+++ b/external/sh/eval.h
@@ -0,0 +1,70 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)eval.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: head/bin/sh/eval.h 279508 2015-03-01 22:32:23Z jilles $
+ */
+
+extern char *commandname;	/* currently executing command */
+extern int exitstatus;		/* exit status of last command */
+extern int oexitstatus;		/* saved exit status */
+extern struct strlist *cmdenviron;  /* environment for builtin command */
+
+
+struct backcmd {		/* result of evalbackcmd */
+	int fd;			/* file descriptor to read from */
+	char *buf;		/* buffer */
+	int nleft;		/* number of chars in buffer */
+	struct job *jp;		/* job structure for command */
+};
+
+void reseteval(void);
+
+/* flags in argument to evaltree/evalstring */
+#define EV_EXIT 01		/* exit after evaluating tree */
+#define EV_TESTED 02		/* exit status is checked; ignore -e flag */
+#define EV_BACKCMD 04		/* command executing within back quotes */
+
+void evalstring(const char *, int);
+union node;	/* BLETCH for ansi C */
+void evaltree(union node *, int);
+void evalbackcmd(union node *, struct backcmd *);
+
+/* in_function returns nonzero if we are currently evaluating a function */
+#define in_function()	funcnest
+extern int funcnest;
+extern int evalskip;
+extern int skipcount;
+
+/* reasons for skipping commands (see comment on breakcmd routine) */
+#define SKIPBREAK	1
+#define SKIPCONT	2
+#define SKIPRETURN	3
diff --git a/external/sh/exec.c b/external/sh/exec.c
new file mode 100644
index 00000000..60e1e545
--- /dev/null
+++ b/external/sh/exec.c
@@ -0,0 +1,771 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)exec.c	8.4 (Berkeley) 6/8/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: head/bin/sh/exec.c 268920 2014-07-20 12:06:52Z jilles $");
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <paths.h>
+#include <stdlib.h>
+
+/*
+ * When commands are first encountered, they are entered in a hash table.
+ * This ensures that a full path search will not have to be done for them
+ * on each invocation.
+ *
+ * We should investigate converting to a linear search, even though that
+ * would make the command name "hash" a misnomer.
+ */
+
+#include "shell.h"
+#include "main.h"
+#include "nodes.h"
+#include "parser.h"
+#include "redir.h"
+#include "eval.h"
+#include "exec.h"
+#include "builtins.h"
+#include "var.h"
+#include "options.h"
+#include "input.h"
+#include "output.h"
+#include "syntax.h"
+#include "memalloc.h"
+#include "error.h"
+#include "mystring.h"
+#include "show.h"
+#include "jobs.h"
+#include "alias.h"
+
+
+#define CMDTABLESIZE 31		/* should be prime */
+
+
+
+struct tblentry {
+	struct tblentry *next;	/* next entry in hash chain */
+	union param param;	/* definition of builtin function */
+	int special;		/* flag for special builtin commands */
+	signed char cmdtype;	/* index identifying command */
+	char cmdname[];		/* name of command */
+};
+
+
+static struct tblentry *cmdtable[CMDTABLESIZE];
+static int cmdtable_cd = 0;	/* cmdtable contains cd-dependent entries */
+int exerrno = 0;			/* Last exec error */
+
+
+static void tryexec(char *, char **, char **);
+static void printentry(struct tblentry *, int);
+static struct tblentry *cmdlookup(const char *, int);
+static void delete_cmd_entry(void);
+static void addcmdentry(const char *, struct cmdentry *);
+
+
+
+/*
+ * Exec a program.  Never returns.  If you change this routine, you may
+ * have to change the find_command routine as well.
+ *
+ * The argv array may be changed and element argv[-1] should be writable.
+ */
+
+void
+shellexec(char **argv, char **envp, const char *path, int idx)
+{
+	char *cmdname;
+	int e;
+
+	if (strchr(argv[0], '/') != NULL) {
+		tryexec(argv[0], argv, envp);
+		e = errno;
+	} else {
+		e = ENOENT;
+		while ((cmdname = padvance(&path, argv[0])) != NULL) {
+			if (--idx < 0 && pathopt == NULL) {
+				tryexec(cmdname, argv, envp);
+				if (errno != ENOENT && errno != ENOTDIR)
+					e = errno;
+				if (e == ENOEXEC)
+					break;
+			}
+			stunalloc(cmdname);
+		}
+	}
+
+	/* Map to POSIX errors */
+	if (e == ENOENT || e == ENOTDIR) {
+		exerrno = 127;
+		exerror(EXEXEC, "%s: not found", argv[0]);
+	} else {
+		exerrno = 126;
+		exerror(EXEXEC, "%s: %s", argv[0], strerror(e));
+	}
+}
+
+
+static void
+tryexec(char *cmd, char **argv, char **envp)
+{
+	int e, in;
+	ssize_t n;
+	char buf[256];
+
+	execve(cmd, argv, envp);
+	e = errno;
+	if (e == ENOEXEC) {
+		INTOFF;
+		in = open(cmd, O_RDONLY | O_NONBLOCK);
+		if (in != -1) {
+			n = pread(in, buf, sizeof buf, 0);
+			close(in);
+			if (n > 0 && memchr(buf, '\0', n) != NULL) {
+				errno = ENOEXEC;
+				return;
+			}
+		}
+		*argv = cmd;
+		*--argv = __DECONST(char *, _PATH_BSHELL);
+		execve(_PATH_BSHELL, argv, envp);
+	}
+	errno = e;
+}
+
+/*
+ * Do a path search.  The variable path (passed by reference) should be
+ * set to the start of the path before the first call; padvance will update
+ * this value as it proceeds.  Successive calls to padvance will return
+ * the possible path expansions in sequence.  If an option (indicated by
+ * a percent sign) appears in the path entry then the global variable
+ * pathopt will be set to point to it; otherwise pathopt will be set to
+ * NULL.
+ */
+
+const char *pathopt;
+
+char *
+padvance(const char **path, const char *name)
+{
+	const char *p, *start;
+	char *q;
+	size_t len, namelen;
+
+	if (*path == NULL)
+		return NULL;
+	start = *path;
+	for (p = start; *p && *p != ':' && *p != '%'; p++)
+		; /* nothing */
+	namelen = strlen(name);
+	len = p - start + namelen + 2;	/* "2" is for '/' and '\0' */
+	STARTSTACKSTR(q);
+	CHECKSTRSPACE(len, q);
+	if (p != start) {
+		memcpy(q, start, p - start);
+		q += p - start;
+		*q++ = '/';
+	}
+	memcpy(q, name, namelen + 1);
+	pathopt = NULL;
+	if (*p == '%') {
+		pathopt = ++p;
+		while (*p && *p != ':')  p++;
+	}
+	if (*p == ':')
+		*path = p + 1;
+	else
+		*path = NULL;
+	return stalloc(len);
+}
+
+
+
+/*** Command hashing code ***/
+
+
+int
+hashcmd(int argc __unused, char **argv __unused)
+{
+	struct tblentry **pp;
+	struct tblentry *cmdp;
+	int c;
+	int verbose;
+	struct cmdentry entry;
+	char *name;
+	int errors;
+
+	errors = 0;
+	verbose = 0;
+	while ((c = nextopt("rv")) != '\0') {
+		if (c == 'r') {
+			clearcmdentry();
+		} else if (c == 'v') {
+			verbose++;
+		}
+	}
+	if (*argptr == NULL) {
+		for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
+			for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
+				if (cmdp->cmdtype == CMDNORMAL)
+					printentry(cmdp, verbose);
+			}
+		}
+		return 0;
+	}
+	while ((name = *argptr) != NULL) {
+		if ((cmdp = cmdlookup(name, 0)) != NULL
+		 && cmdp->cmdtype == CMDNORMAL)
+			delete_cmd_entry();
+		find_command(name, &entry, DO_ERR, pathval());
+		if (entry.cmdtype == CMDUNKNOWN)
+			errors = 1;
+		else if (verbose) {
+			cmdp = cmdlookup(name, 0);
+			if (cmdp != NULL)
+				printentry(cmdp, verbose);
+			else {
+				outfmt(out2, "%s: not found\n", name);
+				errors = 1;
+			}
+			flushall();
+		}
+		argptr++;
+	}
+	return errors;
+}
+
+
+static void
+printentry(struct tblentry *cmdp, int verbose)
+{
+	int idx;
+	const char *path;
+	char *name;
+
+	if (cmdp->cmdtype == CMDNORMAL) {
+		idx = cmdp->param.index;
+		path = pathval();
+		do {
+			name = padvance(&path, cmdp->cmdname);
+			stunalloc(name);
+		} while (--idx >= 0);
+		out1str(name);
+	} else if (cmdp->cmdtype == CMDBUILTIN) {
+		out1fmt("builtin %s", cmdp->cmdname);
+	} else if (cmdp->cmdtype == CMDFUNCTION) {
+		out1fmt("function %s", cmdp->cmdname);
+		if (verbose) {
+			INTOFF;
+			name = commandtext(getfuncnode(cmdp->param.func));
+			out1c(' ');
+			out1str(name);
+			ckfree(name);
+			INTON;
+		}
+#ifdef DEBUG
+	} else {
+		error("internal error: cmdtype %d", cmdp->cmdtype);
+#endif
+	}
+	out1c('\n');
+}
+
+
+
+/*
+ * Resolve a command name.  If you change this routine, you may have to
+ * change the shellexec routine as well.
+ */
+
+void
+find_command(const char *name, struct cmdentry *entry, int act,
+    const char *path)
+{
+	struct tblentry *cmdp, loc_cmd;
+	int idx;
+	char *fullname;
+	struct stat statb;
+	int e;
+	int i;
+	int spec;
+	int cd;
+
+	/* If name contains a slash, don't use the hash table */
+	if (strchr(name, '/') != NULL) {
+		entry->cmdtype = CMDNORMAL;
+		entry->u.index = 0;
+		return;
+	}
+
+	cd = 0;
+
+	/* If name is in the table, and not invalidated by cd, we're done */
+	if ((cmdp = cmdlookup(name, 0)) != NULL) {
+		if (cmdp->cmdtype == CMDFUNCTION && act & DO_NOFUNC)
+			cmdp = NULL;
+		else
+			goto success;
+	}
+
+	/* Check for builtin next */
+	if ((i = find_builtin(name, &spec)) >= 0) {
+		INTOFF;
+		cmdp = cmdlookup(name, 1);
+		if (cmdp->cmdtype == CMDFUNCTION)
+			cmdp = &loc_cmd;
+		cmdp->cmdtype = CMDBUILTIN;
+		cmdp->param.index = i;
+		cmdp->special = spec;
+		INTON;
+		goto success;
+	}
+
+	/* We have to search path. */
+
+	e = ENOENT;
+	idx = -1;
+	for (;(fullname = padvance(&path, name)) != NULL; stunalloc(fullname)) {
+		idx++;
+		if (pathopt) {
+			if (strncmp(pathopt, "func", 4) == 0) {
+				/* handled below */
+			} else {
+				continue; /* ignore unimplemented options */
+			}
+		}
+		if (fullname[0] != '/')
+			cd = 1;
+		if (stat(fullname, &statb) < 0) {
+			if (errno != ENOENT && errno != ENOTDIR)
+				e = errno;
+			continue;
+		}
+		e = EACCES;	/* if we fail, this will be the error */
+		if (!S_ISREG(statb.st_mode))
+			continue;
+		if (pathopt) {		/* this is a %func directory */
+			readcmdfile(fullname);
+			if ((cmdp = cmdlookup(name, 0)) == NULL || cmdp->cmdtype != CMDFUNCTION)
+				error("%s not defined in %s", name, fullname);
+			stunalloc(fullname);
+			goto success;
+		}
+#ifdef notdef
+		if (statb.st_uid == geteuid()) {
+			if ((statb.st_mode & 0100) == 0)
+				goto loop;
+		} else if (statb.st_gid == getegid()) {
+			if ((statb.st_mode & 010) == 0)
+				goto loop;
+		} else {
+			if ((statb.st_mode & 01) == 0)
+				goto loop;
+		}
+#endif
+		TRACE(("searchexec \"%s\" returns \"%s\"\n", name, fullname));
+		INTOFF;
+		stunalloc(fullname);
+		cmdp = cmdlookup(name, 1);
+		if (cmdp->cmdtype == CMDFUNCTION)
+			cmdp = &loc_cmd;
+		cmdp->cmdtype = CMDNORMAL;
+		cmdp->param.index = idx;
+		INTON;
+		goto success;
+	}
+
+	if (act & DO_ERR) {
+		if (e == ENOENT || e == ENOTDIR)
+			outfmt(out2, "%s: not found\n", name);
+		else
+			outfmt(out2, "%s: %s\n", name, strerror(e));
+	}
+	entry->cmdtype = CMDUNKNOWN;
+	entry->u.index = 0;
+	return;
+
+success:
+	if (cd)
+		cmdtable_cd = 1;
+	entry->cmdtype = cmdp->cmdtype;
+	entry->u = cmdp->param;
+	entry->special = cmdp->special;
+}
+
+
+
+/*
+ * Search the table of builtin commands.
+ */
+
+int
+find_builtin(const char *name, int *special)
+{
+	const struct builtincmd *bp;
+
+	for (bp = builtincmd ; bp->name ; bp++) {
+		if (*bp->name == *name && equal(bp->name, name)) {
+			*special = bp->special;
+			return bp->code;
+		}
+	}
+	return -1;
+}
+
+
+
+/*
+ * Called when a cd is done.  If any entry in cmdtable depends on the current
+ * directory, simply clear cmdtable completely.
+ */
+
+void
+hashcd(void)
+{
+	if (cmdtable_cd)
+		clearcmdentry();
+}
+
+
+
+/*
+ * Called before PATH is changed.  The argument is the new value of PATH;
+ * pathval() still returns the old value at this point.  Called with
+ * interrupts off.
+ */
+
+void
+changepath(const char *newval __unused)
+{
+	clearcmdentry();
+}
+
+
+/*
+ * Clear out command entries.  The argument specifies the first entry in
+ * PATH which has changed.
+ */
+
+void
+clearcmdentry(void)
+{
+	struct tblentry **tblp;
+	struct tblentry **pp;
+	struct tblentry *cmdp;
+
+	INTOFF;
+	for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) {
+		pp = tblp;
+		while ((cmdp = *pp) != NULL) {
+			if (cmdp->cmdtype == CMDNORMAL) {
+				*pp = cmdp->next;
+				ckfree(cmdp);
+			} else {
+				pp = &cmdp->next;
+			}
+		}
+	}
+	cmdtable_cd = 0;
+	INTON;
+}
+
+
+/*
+ * Locate a command in the command hash table.  If "add" is nonzero,
+ * add the command to the table if it is not already present.  The
+ * variable "lastcmdentry" is set to point to the address of the link
+ * pointing to the entry, so that delete_cmd_entry can delete the
+ * entry.
+ */
+
+static struct tblentry **lastcmdentry;
+
+
+static struct tblentry *
+cmdlookup(const char *name, int add)
+{
+	int hashval;
+	const char *p;
+	struct tblentry *cmdp;
+	struct tblentry **pp;
+	size_t len;
+
+	p = name;
+	hashval = *p << 4;
+	while (*p)
+		hashval += *p++;
+	hashval &= 0x7FFF;
+	pp = &cmdtable[hashval % CMDTABLESIZE];
+	for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
+		if (equal(cmdp->cmdname, name))
+			break;
+		pp = &cmdp->next;
+	}
+	if (add && cmdp == NULL) {
+		INTOFF;
+		len = strlen(name);
+		cmdp = *pp = ckmalloc(sizeof (struct tblentry) + len + 1);
+		cmdp->next = NULL;
+		cmdp->cmdtype = CMDUNKNOWN;
+		memcpy(cmdp->cmdname, name, len + 1);
+		INTON;
+	}
+	lastcmdentry = pp;
+	return cmdp;
+}
+
+/*
+ * Delete the command entry returned on the last lookup.
+ */
+
+static void
+delete_cmd_entry(void)
+{
+	struct tblentry *cmdp;
+
+	INTOFF;
+	cmdp = *lastcmdentry;
+	*lastcmdentry = cmdp->next;
+	ckfree(cmdp);
+	INTON;
+}
+
+
+
+/*
+ * Add a new command entry, replacing any existing command entry for
+ * the same name.
+ */
+
+static void
+addcmdentry(const char *name, struct cmdentry *entry)
+{
+	struct tblentry *cmdp;
+
+	INTOFF;
+	cmdp = cmdlookup(name, 1);
+	if (cmdp->cmdtype == CMDFUNCTION) {
+		unreffunc(cmdp->param.func);
+	}
+	cmdp->cmdtype = entry->cmdtype;
+	cmdp->param = entry->u;
+	INTON;
+}
+
+
+/*
+ * Define a shell function.
+ */
+
+void
+defun(const char *name, union node *func)
+{
+	struct cmdentry entry;
+
+	INTOFF;
+	entry.cmdtype = CMDFUNCTION;
+	entry.u.func = copyfunc(func);
+	addcmdentry(name, &entry);
+	INTON;
+}
+
+
+/*
+ * Delete a function if it exists.
+ * Called with interrupts off.
+ */
+
+int
+unsetfunc(const char *name)
+{
+	struct tblentry *cmdp;
+
+	if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) {
+		unreffunc(cmdp->param.func);
+		delete_cmd_entry();
+		return (0);
+	}
+	return (0);
+}
+
+
+/*
+ * Check if a function by a certain name exists.
+ */
+int
+isfunc(const char *name)
+{
+	struct tblentry *cmdp;
+	cmdp = cmdlookup(name, 0);
+	return (cmdp != NULL && cmdp->cmdtype == CMDFUNCTION);
+}
+
+
+/*
+ * Shared code for the following builtin commands:
+ *    type, command -v, command -V
+ */
+
+int
+typecmd_impl(int argc, char **argv, int cmd, const char *path)
+{
+	struct cmdentry entry;
+	struct tblentry *cmdp;
+	const char *const *pp;
+	struct alias *ap;
+	int i;
+	int error1 = 0;
+
+	if (path != pathval())
+		clearcmdentry();
+
+	for (i = 1; i < argc; i++) {
+		/* First look at the keywords */
+		for (pp = parsekwd; *pp; pp++)
+			if (**pp == *argv[i] && equal(*pp, argv[i]))
+				break;
+
+		if (*pp) {
+			if (cmd == TYPECMD_SMALLV)
+				out1fmt("%s\n", argv[i]);
+			else
+				out1fmt("%s is a shell keyword\n", argv[i]);
+			continue;
+		}
+
+		/* Then look at the aliases */
+		if ((ap = lookupalias(argv[i], 1)) != NULL) {
+			if (cmd == TYPECMD_SMALLV) {
+				out1fmt("alias %s=", argv[i]);
+				out1qstr(ap->val);
+				outcslow('\n', out1);
+			} else
+				out1fmt("%s is an alias for %s\n", argv[i],
+				    ap->val);
+			continue;
+		}
+
+		/* Then check if it is a tracked alias */
+		if ((cmdp = cmdlookup(argv[i], 0)) != NULL) {
+			entry.cmdtype = cmdp->cmdtype;
+			entry.u = cmdp->param;
+			entry.special = cmdp->special;
+		}
+		else {
+			/* Finally use brute force */
+			find_command(argv[i], &entry, 0, path);
+		}
+
+		switch (entry.cmdtype) {
+		case CMDNORMAL: {
+			if (strchr(argv[i], '/') == NULL) {
+				const char *path2 = path;
+				char *name;
+				int j = entry.u.index;
+				do {
+					name = padvance(&path2, argv[i]);
+					stunalloc(name);
+				} while (--j >= 0);
+				if (cmd == TYPECMD_SMALLV)
+					out1fmt("%s\n", name);
+				else
+					out1fmt("%s is%s %s\n", argv[i],
+					    (cmdp && cmd == TYPECMD_TYPE) ?
+						" a tracked alias for" : "",
+					    name);
+			} else {
+				if (eaccess(argv[i], X_OK) == 0) {
+					if (cmd == TYPECMD_SMALLV)
+						out1fmt("%s\n", argv[i]);
+					else
+						out1fmt("%s is %s\n", argv[i],
+						    argv[i]);
+				} else {
+					if (cmd != TYPECMD_SMALLV)
+						outfmt(out2, "%s: %s\n",
+						    argv[i], strerror(errno));
+					error1 |= 127;
+				}
+			}
+			break;
+		}
+		case CMDFUNCTION:
+			if (cmd == TYPECMD_SMALLV)
+				out1fmt("%s\n", argv[i]);
+			else
+				out1fmt("%s is a shell function\n", argv[i]);
+			break;
+
+		case CMDBUILTIN:
+			if (cmd == TYPECMD_SMALLV)
+				out1fmt("%s\n", argv[i]);
+			else if (entry.special)
+				out1fmt("%s is a special shell builtin\n",
+				    argv[i]);
+			else
+				out1fmt("%s is a shell builtin\n", argv[i]);
+			break;
+
+		default:
+			if (cmd != TYPECMD_SMALLV)
+				outfmt(out2, "%s: not found\n", argv[i]);
+			error1 |= 127;
+			break;
+		}
+	}
+
+	if (path != pathval())
+		clearcmdentry();
+
+	return error1;
+}
+
+/*
+ * Locate and print what a word is...
+ */
+
+int
+typecmd(int argc, char **argv)
+{
+	if (argc > 2 && strcmp(argv[1], "--") == 0)
+		argc--, argv++;
+	return typecmd_impl(argc, argv, TYPECMD_TYPE, bltinlookup("PATH", 1));
+}
diff --git a/external/sh/exec.h b/external/sh/exec.h
new file mode 100644
index 00000000..0bd6df32
--- /dev/null
+++ b/external/sh/exec.h
@@ -0,0 +1,77 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)exec.h	8.3 (Berkeley) 6/8/95
+ * $FreeBSD: head/bin/sh/exec.h 238468 2012-07-15 10:19:43Z jilles $
+ */
+
+/* values of cmdtype */
+#define CMDUNKNOWN -1		/* no entry in table for command */
+#define CMDNORMAL 0		/* command is an executable program */
+#define CMDBUILTIN 1		/* command is a shell builtin */
+#define CMDFUNCTION 2		/* command is a shell function */
+
+/* values for typecmd_impl's third parameter */
+enum {
+	TYPECMD_SMALLV,		/* command -v */
+	TYPECMD_BIGV,		/* command -V */
+	TYPECMD_TYPE		/* type */
+};
+
+union node;
+struct cmdentry {
+	int cmdtype;
+	union param {
+		int index;
+		struct funcdef *func;
+	} u;
+	int special;
+};
+
+
+/* action to find_command() */
+#define DO_ERR		0x01	/* prints errors */
+#define DO_NOFUNC	0x02	/* don't return shell functions, for command */
+
+extern const char *pathopt;	/* set by padvance */
+extern int exerrno;		/* last exec error */
+
+void shellexec(char **, char **, const char *, int) __dead2;
+char *padvance(const char **, const char *);
+void find_command(const char *, struct cmdentry *, int, const char *);
+int find_builtin(const char *, int *);
+void hashcd(void);
+void changepath(const char *);
+void defun(const char *, union node *);
+int unsetfunc(const char *);
+int isfunc(const char *);
+int typecmd_impl(int, char **, int, const char *);
+void clearcmdentry(void);
diff --git a/external/sh/expand.c b/external/sh/expand.c
new file mode 100644
index 00000000..fd6385e2
--- /dev/null
+++ b/external/sh/expand.c
@@ -0,0 +1,1663 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ * Copyright (c) 1997-2005
+ *	Herbert Xu <herbert@gondor.apana.org.au>.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)expand.c	8.5 (Berkeley) 5/15/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: head/bin/sh/expand.c 279330 2015-02-26 20:59:18Z nwhitehorn $");
+
+#include <sys/types.h>
+#include <sys/time.h>
+#include <sys/stat.h>
+#include <dirent.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <limits.h>
+#include <pwd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <wchar.h>
+#include <wctype.h>
+
+/*
+ * Routines to expand arguments to commands.  We have to deal with
+ * backquotes, shell variables, and file metacharacters.
+ */
+
+#include "shell.h"
+#include "main.h"
+#include "nodes.h"
+#include "eval.h"
+#include "expand.h"
+#include "syntax.h"
+#include "parser.h"
+#include "jobs.h"
+#include "options.h"
+#include "var.h"
+#include "input.h"
+#include "output.h"
+#include "memalloc.h"
+#include "error.h"
+#include "mystring.h"
+#include "arith.h"
+#include "show.h"
+#include "builtins.h"
+
+/*
+ * Structure specifying which parts of the string should be searched
+ * for IFS characters.
+ */
+
+struct ifsregion {
+	struct ifsregion *next;	/* next region in list */
+	int begoff;		/* offset of start of region */
+	int endoff;		/* offset of end of region */
+	int inquotes;		/* search for nul bytes only */
+};
+
+
+static char *expdest;			/* output of current string */
+static struct nodelist *argbackq;	/* list of back quote expressions */
+static struct ifsregion ifsfirst;	/* first struct in list of ifs regions */
+static struct ifsregion *ifslastp;	/* last struct in list */
+static struct arglist exparg;		/* holds expanded arg list */
+
+static char *argstr(char *, int);
+static char *exptilde(char *, int);
+static char *expari(char *);
+static void expbackq(union node *, int, int);
+static int subevalvar(char *, char *, int, int, int, int, int);
+static char *evalvar(char *, int);
+static int varisset(const char *, int);
+static void strtodest(const char *, int, int, int);
+static void varvalue(const char *, int, int, int);
+static void recordregion(int, int, int);
+static void removerecordregions(int);
+static void ifsbreakup(char *, struct arglist *);
+static void expandmeta(struct strlist *);
+static void expmeta(char *, char *);
+static void addfname(char *);
+static struct strlist *expsort(struct strlist *);
+static struct strlist *msort(struct strlist *, int);
+static int patmatch(const char *, const char *, int);
+static char *cvtnum(int, char *);
+static int collate_range_cmp(wchar_t, wchar_t);
+
+static int
+collate_range_cmp(wchar_t c1, wchar_t c2)
+{
+	static wchar_t s1[2], s2[2];
+
+	s1[0] = c1;
+	s2[0] = c2;
+	return (wcscoll(s1, s2));
+}
+
+static char *
+stputs_quotes(const char *data, const char *syntax, char *p)
+{
+	while (*data) {
+		CHECKSTRSPACE(2, p);
+		if (syntax[(int)*data] == CCTL)
+			USTPUTC(CTLESC, p);
+		USTPUTC(*data++, p);
+	}
+	return (p);
+}
+#define STPUTS_QUOTES(data, syntax, p) p = stputs_quotes((data), syntax, p)
+
+/*
+ * Perform expansions on an argument, placing the resulting list of arguments
+ * in arglist.  Parameter expansion, command substitution and arithmetic
+ * expansion are always performed; additional expansions can be requested
+ * via flag (EXP_*).
+ * The result is left in the stack string.
+ * When arglist is NULL, perform here document expansion.
+ *
+ * Caution: this function uses global state and is not reentrant.
+ * However, a new invocation after an interrupted invocation is safe
+ * and will reset the global state for the new call.
+ */
+void
+expandarg(union node *arg, struct arglist *arglist, int flag)
+{
+	struct strlist *sp;
+	char *p;
+
+	argbackq = arg->narg.backquote;
+	STARTSTACKSTR(expdest);
+	ifsfirst.next = NULL;
+	ifslastp = NULL;
+	argstr(arg->narg.text, flag);
+	if (arglist == NULL) {
+		STACKSTRNUL(expdest);
+		return;			/* here document expanded */
+	}
+	STPUTC('\0', expdest);
+	p = grabstackstr(expdest);
+	exparg.lastp = &exparg.list;
+	if (flag & EXP_FULL) {
+		ifsbreakup(p, &exparg);
+		*exparg.lastp = NULL;
+		exparg.lastp = &exparg.list;
+		expandmeta(exparg.list);
+	} else {
+		sp = (struct strlist *)stalloc(sizeof (struct strlist));
+		sp->text = p;
+		*exparg.lastp = sp;
+		exparg.lastp = &sp->next;
+	}
+	while (ifsfirst.next != NULL) {
+		struct ifsregion *ifsp;
+		INTOFF;
+		ifsp = ifsfirst.next->next;
+		ckfree(ifsfirst.next);
+		ifsfirst.next = ifsp;
+		INTON;
+	}
+	*exparg.lastp = NULL;
+	if (exparg.list) {
+		*arglist->lastp = exparg.list;
+		arglist->lastp = exparg.lastp;
+	}
+}
+
+
+
+/*
+ * Perform parameter expansion, command substitution and arithmetic
+ * expansion, and tilde expansion if requested via EXP_TILDE/EXP_VARTILDE.
+ * Processing ends at a CTLENDVAR or CTLENDARI character as well as '\0'.
+ * This is used to expand word in ${var+word} etc.
+ * If EXP_FULL or EXP_CASE are set, keep and/or generate CTLESC
+ * characters to allow for further processing.
+ * If EXP_FULL is set, also preserve CTLQUOTEMARK characters.
+ */
+static char *
+argstr(char *p, int flag)
+{
+	char c;
+	int quotes = flag & (EXP_FULL | EXP_CASE);	/* do CTLESC */
+	int firsteq = 1;
+	int split_lit;
+	int lit_quoted;
+
+	split_lit = flag & EXP_SPLIT_LIT;
+	lit_quoted = flag & EXP_LIT_QUOTED;
+	flag &= ~(EXP_SPLIT_LIT | EXP_LIT_QUOTED);
+	if (*p == '~' && (flag & (EXP_TILDE | EXP_VARTILDE)))
+		p = exptilde(p, flag);
+	for (;;) {
+		CHECKSTRSPACE(2, expdest);
+		switch (c = *p++) {
+		case '\0':
+			return (p - 1);
+		case CTLENDVAR:
+		case CTLENDARI:
+			return (p);
+		case CTLQUOTEMARK:
+			lit_quoted = 1;
+			/* "$@" syntax adherence hack */
+			if (p[0] == CTLVAR && p[2] == '@' && p[3] == '=')
+				break;
+			if ((flag & EXP_FULL) != 0)
+				USTPUTC(c, expdest);
+			break;
+		case CTLQUOTEEND:
+			lit_quoted = 0;
+			break;
+		case CTLESC:
+			if (quotes)
+				USTPUTC(c, expdest);
+			c = *p++;
+			USTPUTC(c, expdest);
+			if (split_lit && !lit_quoted)
+				recordregion(expdest - stackblock() -
+				    (quotes ? 2 : 1),
+				    expdest - stackblock(), 0);
+			break;
+		case CTLVAR:
+			p = evalvar(p, flag);
+			break;
+		case CTLBACKQ:
+		case CTLBACKQ|CTLQUOTE:
+			expbackq(argbackq->n, c & CTLQUOTE, flag);
+			argbackq = argbackq->next;
+			break;
+		case CTLARI:
+			p = expari(p);
+			break;
+		case ':':
+		case '=':
+			/*
+			 * sort of a hack - expand tildes in variable
+			 * assignments (after the first '=' and after ':'s).
+			 */
+			USTPUTC(c, expdest);
+			if (split_lit && !lit_quoted)
+				recordregion(expdest - stackblock() - 1,
+				    expdest - stackblock(), 0);
+			if (flag & EXP_VARTILDE && *p == '~' &&
+			    (c != '=' || firsteq)) {
+				if (c == '=')
+					firsteq = 0;
+				p = exptilde(p, flag);
+			}
+			break;
+		default:
+			USTPUTC(c, expdest);
+			if (split_lit && !lit_quoted)
+				recordregion(expdest - stackblock() - 1,
+				    expdest - stackblock(), 0);
+		}
+	}
+}
+
+/*
+ * Perform tilde expansion, placing the result in the stack string and
+ * returning the next position in the input string to process.
+ */
+static char *
+exptilde(char *p, int flag)
+{
+	char c, *startp = p;
+	struct passwd *pw;
+	char *home;
+
+	for (;;) {
+		c = *p;
+		switch(c) {
+		case CTLESC: /* This means CTL* are always considered quoted. */
+		case CTLVAR:
+		case CTLBACKQ:
+		case CTLBACKQ | CTLQUOTE:
+		case CTLARI:
+		case CTLENDARI:
+		case CTLQUOTEMARK:
+			return (startp);
+		case ':':
+			if ((flag & EXP_VARTILDE) == 0)
+				break;
+			/* FALLTHROUGH */
+		case '\0':
+		case '/':
+		case CTLENDVAR:
+			*p = '\0';
+			if (*(startp+1) == '\0') {
+				home = lookupvar("HOME");
+			} else {
+				pw = getpwnam(startp+1);
+				home = pw != NULL ? pw->pw_dir : NULL;
+			}
+			*p = c;
+			if (home == NULL || *home == '\0')
+				return (startp);
+			strtodest(home, flag, VSNORMAL, 1);
+			return (p);
+		}
+		p++;
+	}
+}
+
+
+static void
+removerecordregions(int endoff)
+{
+	if (ifslastp == NULL)
+		return;
+
+	if (ifsfirst.endoff > endoff) {
+		while (ifsfirst.next != NULL) {
+			struct ifsregion *ifsp;
+			INTOFF;
+			ifsp = ifsfirst.next->next;
+			ckfree(ifsfirst.next);
+			ifsfirst.next = ifsp;
+			INTON;
+		}
+		if (ifsfirst.begoff > endoff)
+			ifslastp = NULL;
+		else {
+			ifslastp = &ifsfirst;
+			ifsfirst.endoff = endoff;
+		}
+		return;
+	}
+
+	ifslastp = &ifsfirst;
+	while (ifslastp->next && ifslastp->next->begoff < endoff)
+		ifslastp=ifslastp->next;
+	while (ifslastp->next != NULL) {
+		struct ifsregion *ifsp;
+		INTOFF;
+		ifsp = ifslastp->next->next;
+		ckfree(ifslastp->next);
+		ifslastp->next = ifsp;
+		INTON;
+	}
+	if (ifslastp->endoff > endoff)
+		ifslastp->endoff = endoff;
+}
+
+/*
+ * Expand arithmetic expression.
+ * Note that flag is not required as digits never require CTLESC characters.
+ */
+static char *
+expari(char *p)
+{
+	char *q, *start;
+	arith_t result;
+	int begoff;
+	int quoted;
+	int adj;
+
+	quoted = *p++ == '"';
+	begoff = expdest - stackblock();
+	p = argstr(p, 0);
+	removerecordregions(begoff);
+	STPUTC('\0', expdest);
+	start = stackblock() + begoff;
+
+	q = grabstackstr(expdest);
+	result = arith(start);
+	ungrabstackstr(q, expdest);
+
+	start = stackblock() + begoff;
+	adj = start - expdest;
+	STADJUST(adj, expdest);
+
+	CHECKSTRSPACE((int)(DIGITS(result) + 1), expdest);
+	fmtstr(expdest, DIGITS(result), ARITH_FORMAT_STR, result);
+	adj = strlen(expdest);
+	STADJUST(adj, expdest);
+	if (!quoted)
+		recordregion(begoff, expdest - stackblock(), 0);
+	return p;
+}
+
+
+/*
+ * Perform command substitution.
+ */
+static void
+expbackq(union node *cmd, int quoted, int flag)
+{
+	struct backcmd in;
+	int i;
+	char buf[128];
+	char *p;
+	char *dest = expdest;
+	struct ifsregion saveifs, *savelastp;
+	struct nodelist *saveargbackq;
+	char lastc;
+	int startloc = dest - stackblock();
+	char const *syntax = quoted? DQSYNTAX : BASESYNTAX;
+	int quotes = flag & (EXP_FULL | EXP_CASE);
+	size_t nnl;
+
+	INTOFF;
+	saveifs = ifsfirst;
+	savelastp = ifslastp;
+	saveargbackq = argbackq;
+	p = grabstackstr(dest);
+	evalbackcmd(cmd, &in);
+	ungrabstackstr(p, dest);
+	ifsfirst = saveifs;
+	ifslastp = savelastp;
+	argbackq = saveargbackq;
+
+	p = in.buf;
+	lastc = '\0';
+	nnl = 0;
+	/* Don't copy trailing newlines */
+	for (;;) {
+		if (--in.nleft < 0) {
+			if (in.fd < 0)
+				break;
+			while ((i = read(in.fd, buf, sizeof buf)) < 0 && errno == EINTR);
+			TRACE(("expbackq: read returns %d\n", i));
+			if (i <= 0)
+				break;
+			p = buf;
+			in.nleft = i - 1;
+		}
+		lastc = *p++;
+		if (lastc != '\0') {
+			if (lastc == '\n') {
+				nnl++;
+			} else {
+				CHECKSTRSPACE(nnl + 2, dest);
+				while (nnl > 0) {
+					nnl--;
+					USTPUTC('\n', dest);
+				}
+				if (quotes && syntax[(int)lastc] == CCTL)
+					USTPUTC(CTLESC, dest);
+				USTPUTC(lastc, dest);
+			}
+		}
+	}
+
+	if (in.fd >= 0)
+		close(in.fd);
+	if (in.buf)
+		ckfree(in.buf);
+	if (in.jp)
+		exitstatus = waitforjob(in.jp, (int *)NULL);
+	if (quoted == 0)
+		recordregion(startloc, dest - stackblock(), 0);
+	TRACE(("expbackq: size=%td: \"%.*s\"\n",
+		((dest - stackblock()) - startloc),
+		(int)((dest - stackblock()) - startloc),
+		stackblock() + startloc));
+	expdest = dest;
+	INTON;
+}
+
+
+
+static void
+recordleft(const char *str, const char *loc, char *startp)
+{
+	int amount;
+
+	amount = ((str - 1) - (loc - startp)) - expdest;
+	STADJUST(amount, expdest);
+	while (loc != str - 1)
+		*startp++ = *loc++;
+}
+
+static int
+subevalvar(char *p, char *str, int strloc, int subtype, int startloc,
+  int varflags, int quotes)
+{
+	char *startp;
+	char *loc = NULL;
+	char *q;
+	int c = 0;
+	struct nodelist *saveargbackq = argbackq;
+	int amount;
+
+	argstr(p, (subtype == VSTRIMLEFT || subtype == VSTRIMLEFTMAX ||
+	    subtype == VSTRIMRIGHT || subtype == VSTRIMRIGHTMAX ?
+	    EXP_CASE : 0) | EXP_TILDE);
+	STACKSTRNUL(expdest);
+	argbackq = saveargbackq;
+	startp = stackblock() + startloc;
+	if (str == NULL)
+	    str = stackblock() + strloc;
+
+	switch (subtype) {
+	case VSASSIGN:
+		setvar(str, startp, 0);
+		amount = startp - expdest;
+		STADJUST(amount, expdest);
+		varflags &= ~VSNUL;
+		return 1;
+
+	case VSQUESTION:
+		if (*p != CTLENDVAR) {
+			outfmt(out2, "%s\n", startp);
+			error((char *)NULL);
+		}
+		error("%.*s: parameter %snot set", (int)(p - str - 1),
+		      str, (varflags & VSNUL) ? "null or " : "");
+		return 0;
+
+	case VSTRIMLEFT:
+		for (loc = startp; loc < str; loc++) {
+			c = *loc;
+			*loc = '\0';
+			if (patmatch(str, startp, quotes)) {
+				*loc = c;
+				recordleft(str, loc, startp);
+				return 1;
+			}
+			*loc = c;
+			if (quotes && *loc == CTLESC)
+				loc++;
+		}
+		return 0;
+
+	case VSTRIMLEFTMAX:
+		for (loc = str - 1; loc >= startp;) {
+			c = *loc;
+			*loc = '\0';
+			if (patmatch(str, startp, quotes)) {
+				*loc = c;
+				recordleft(str, loc, startp);
+				return 1;
+			}
+			*loc = c;
+			loc--;
+			if (quotes && loc > startp && *(loc - 1) == CTLESC) {
+				for (q = startp; q < loc; q++)
+					if (*q == CTLESC)
+						q++;
+				if (q > loc)
+					loc--;
+			}
+		}
+		return 0;
+
+	case VSTRIMRIGHT:
+		for (loc = str - 1; loc >= startp;) {
+			if (patmatch(str, loc, quotes)) {
+				amount = loc - expdest;
+				STADJUST(amount, expdest);
+				return 1;
+			}
+			loc--;
+			if (quotes && loc > startp && *(loc - 1) == CTLESC) {
+				for (q = startp; q < loc; q++)
+					if (*q == CTLESC)
+						q++;
+				if (q > loc)
+					loc--;
+			}
+		}
+		return 0;
+
+	case VSTRIMRIGHTMAX:
+		for (loc = startp; loc < str - 1; loc++) {
+			if (patmatch(str, loc, quotes)) {
+				amount = loc - expdest;
+				STADJUST(amount, expdest);
+				return 1;
+			}
+			if (quotes && *loc == CTLESC)
+				loc++;
+		}
+		return 0;
+
+
+	default:
+		abort();
+	}
+}
+
+
+/*
+ * Expand a variable, and return a pointer to the next character in the
+ * input string.
+ */
+
+static char *
+evalvar(char *p, int flag)
+{
+	int subtype;
+	int varflags;
+	char *var;
+	const char *val;
+	int patloc;
+	int c;
+	int set;
+	int special;
+	int startloc;
+	int varlen;
+	int varlenb;
+	int easy;
+	int quotes = flag & (EXP_FULL | EXP_CASE);
+	int record = 0;
+
+	varflags = (unsigned char)*p++;
+	subtype = varflags & VSTYPE;
+	var = p;
+	special = 0;
+	if (! is_name(*p))
+		special = 1;
+	p = strchr(p, '=') + 1;
+again: /* jump here after setting a variable with ${var=text} */
+	if (varflags & VSLINENO) {
+		set = 1;
+		special = 1;
+		val = NULL;
+	} else if (special) {
+		set = varisset(var, varflags & VSNUL);
+		val = NULL;
+	} else {
+		val = bltinlookup(var, 1);
+		if (val == NULL || ((varflags & VSNUL) && val[0] == '\0')) {
+			val = NULL;
+			set = 0;
+		} else
+			set = 1;
+	}
+	varlen = 0;
+	startloc = expdest - stackblock();
+	if (!set && uflag && *var != '@' && *var != '*') {
+		switch (subtype) {
+		case VSNORMAL:
+		case VSTRIMLEFT:
+		case VSTRIMLEFTMAX:
+		case VSTRIMRIGHT:
+		case VSTRIMRIGHTMAX:
+		case VSLENGTH:
+			error("%.*s: parameter not set", (int)(p - var - 1),
+			    var);
+		}
+	}
+	if (set && subtype != VSPLUS) {
+		/* insert the value of the variable */
+		if (special) {
+			if (varflags & VSLINENO)
+				STPUTBIN(var, p - var - 1, expdest);
+			else
+				varvalue(var, varflags & VSQUOTE, subtype, flag);
+			if (subtype == VSLENGTH) {
+				varlenb = expdest - stackblock() - startloc;
+				varlen = varlenb;
+				if (localeisutf8) {
+					val = stackblock() + startloc;
+					for (;val != expdest; val++)
+						if ((*val & 0xC0) == 0x80)
+							varlen--;
+				}
+				STADJUST(-varlenb, expdest);
+			}
+		} else {
+			if (subtype == VSLENGTH) {
+				for (;*val; val++)
+					if (!localeisutf8 ||
+					    (*val & 0xC0) != 0x80)
+						varlen++;
+			}
+			else
+				strtodest(val, flag, subtype,
+				    varflags & VSQUOTE);
+		}
+	}
+
+	if (subtype == VSPLUS)
+		set = ! set;
+
+	easy = ((varflags & VSQUOTE) == 0 ||
+		(*var == '@' && shellparam.nparam != 1));
+
+
+	switch (subtype) {
+	case VSLENGTH:
+		expdest = cvtnum(varlen, expdest);
+		record = 1;
+		break;
+
+	case VSNORMAL:
+		record = easy;
+		break;
+
+	case VSPLUS:
+	case VSMINUS:
+		if (!set) {
+			argstr(p, flag | (flag & EXP_FULL ? EXP_SPLIT_LIT : 0) |
+			    (varflags & VSQUOTE ? EXP_LIT_QUOTED : 0));
+			break;
+		}
+		record = easy;
+		break;
+
+	case VSTRIMLEFT:
+	case VSTRIMLEFTMAX:
+	case VSTRIMRIGHT:
+	case VSTRIMRIGHTMAX:
+		if (!set)
+			break;
+		/*
+		 * Terminate the string and start recording the pattern
+		 * right after it
+		 */
+		STPUTC('\0', expdest);
+		patloc = expdest - stackblock();
+		if (subevalvar(p, NULL, patloc, subtype,
+		    startloc, varflags, quotes) == 0) {
+			int amount = (expdest - stackblock() - patloc) + 1;
+			STADJUST(-amount, expdest);
+		}
+		/* Remove any recorded regions beyond start of variable */
+		removerecordregions(startloc);
+		record = 1;
+		break;
+
+	case VSASSIGN:
+	case VSQUESTION:
+		if (!set) {
+			if (subevalvar(p, var, 0, subtype, startloc, varflags,
+			    quotes)) {
+				varflags &= ~VSNUL;
+				/*
+				 * Remove any recorded regions beyond
+				 * start of variable
+				 */
+				removerecordregions(startloc);
+				goto again;
+			}
+			break;
+		}
+		record = easy;
+		break;
+
+	case VSERROR:
+		c = p - var - 1;
+		error("${%.*s%s}: Bad substitution", c, var,
+		    (c > 0 && *p != CTLENDVAR) ? "..." : "");
+
+	default:
+		abort();
+	}
+
+	if (record)
+		recordregion(startloc, expdest - stackblock(),
+		    varflags & VSQUOTE || (ifsset() && ifsval()[0] == '\0' &&
+		    (*var == '@' || *var == '*')));
+
+	if (subtype != VSNORMAL) {	/* skip to end of alternative */
+		int nesting = 1;
+		for (;;) {
+			if ((c = *p++) == CTLESC)
+				p++;
+			else if (c == CTLBACKQ || c == (CTLBACKQ|CTLQUOTE)) {
+				if (set)
+					argbackq = argbackq->next;
+			} else if (c == CTLVAR) {
+				if ((*p++ & VSTYPE) != VSNORMAL)
+					nesting++;
+			} else if (c == CTLENDVAR) {
+				if (--nesting == 0)
+					break;
+			}
+		}
+	}
+	return p;
+}
+
+
+
+/*
+ * Test whether a specialized variable is set.
+ */
+
+static int
+varisset(const char *name, int nulok)
+{
+
+	if (*name == '!')
+		return backgndpidset();
+	else if (*name == '@' || *name == '*') {
+		if (*shellparam.p == NULL)
+			return 0;
+
+		if (nulok) {
+			char **av;
+
+			for (av = shellparam.p; *av; av++)
+				if (**av != '\0')
+					return 1;
+			return 0;
+		}
+	} else if (is_digit(*name)) {
+		char *ap;
+		long num;
+
+		errno = 0;
+		num = strtol(name, NULL, 10);
+		if (errno != 0 || num > shellparam.nparam)
+			return 0;
+
+		if (num == 0)
+			ap = arg0;
+		else
+			ap = shellparam.p[num - 1];
+
+		if (nulok && (ap == NULL || *ap == '\0'))
+			return 0;
+	}
+	return 1;
+}
+
+static void
+strtodest(const char *p, int flag, int subtype, int quoted)
+{
+	if (flag & (EXP_FULL | EXP_CASE) && subtype != VSLENGTH)
+		STPUTS_QUOTES(p, quoted ? DQSYNTAX : BASESYNTAX, expdest);
+	else
+		STPUTS(p, expdest);
+}
+
+/*
+ * Add the value of a specialized variable to the stack string.
+ */
+
+static void
+varvalue(const char *name, int quoted, int subtype, int flag)
+{
+	int num;
+	char *p;
+	int i;
+	char sep[2];
+	char **ap;
+
+	switch (*name) {
+	case '$':
+		num = rootpid;
+		break;
+	case '?':
+		num = oexitstatus;
+		break;
+	case '#':
+		num = shellparam.nparam;
+		break;
+	case '!':
+		num = backgndpidval();
+		break;
+	case '-':
+		for (i = 0 ; i < NOPTS ; i++) {
+			if (optlist[i].val)
+				STPUTC(optlist[i].letter, expdest);
+		}
+		return;
+	case '@':
+		if (flag & EXP_FULL && quoted) {
+			for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
+				strtodest(p, flag, subtype, quoted);
+				if (*ap)
+					STPUTC('\0', expdest);
+			}
+			return;
+		}
+		/* FALLTHROUGH */
+	case '*':
+		if (ifsset())
+			sep[0] = ifsval()[0];
+		else
+			sep[0] = ' ';
+		sep[1] = '\0';
+		for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
+			strtodest(p, flag, subtype, quoted);
+			if (!*ap)
+				break;
+			if (sep[0])
+				strtodest(sep, flag, subtype, quoted);
+			else if (flag & EXP_FULL && !quoted && **ap != '\0')
+				STPUTC('\0', expdest);
+		}
+		return;
+	default:
+		if (is_digit(*name)) {
+			num = atoi(name);
+			if (num == 0)
+				p = arg0;
+			else if (num > 0 && num <= shellparam.nparam)
+				p = shellparam.p[num - 1];
+			else
+				return;
+			strtodest(p, flag, subtype, quoted);
+		}
+		return;
+	}
+	expdest = cvtnum(num, expdest);
+}
+
+
+
+/*
+ * Record the fact that we have to scan this region of the
+ * string for IFS characters.
+ */
+
+static void
+recordregion(int start, int end, int inquotes)
+{
+	struct ifsregion *ifsp;
+
+	INTOFF;
+	if (ifslastp == NULL) {
+		ifsp = &ifsfirst;
+	} else {
+		if (ifslastp->endoff == start
+		    && ifslastp->inquotes == inquotes) {
+			/* extend previous area */
+			ifslastp->endoff = end;
+			INTON;
+			return;
+		}
+		ifsp = (struct ifsregion *)ckmalloc(sizeof (struct ifsregion));
+		ifslastp->next = ifsp;
+	}
+	ifslastp = ifsp;
+	ifslastp->next = NULL;
+	ifslastp->begoff = start;
+	ifslastp->endoff = end;
+	ifslastp->inquotes = inquotes;
+	INTON;
+}
+
+
+
+/*
+ * Break the argument string into pieces based upon IFS and add the
+ * strings to the argument list.  The regions of the string to be
+ * searched for IFS characters have been stored by recordregion.
+ * CTLESC characters are preserved but have little effect in this pass
+ * other than escaping CTL* characters.  In particular, they do not escape
+ * IFS characters: that should be done with the ifsregion mechanism.
+ * CTLQUOTEMARK characters are used to preserve empty quoted strings.
+ * This pass treats them as a regular character, making the string non-empty.
+ * Later, they are removed along with the other CTL* characters.
+ */
+static void
+ifsbreakup(char *string, struct arglist *arglist)
+{
+	struct ifsregion *ifsp;
+	struct strlist *sp;
+	char *start;
+	char *p;
+	char *q;
+	const char *ifs;
+	const char *ifsspc;
+	int had_param_ch = 0;
+
+	start = string;
+
+	if (ifslastp == NULL) {
+		/* Return entire argument, IFS doesn't apply to any of it */
+		sp = (struct strlist *)stalloc(sizeof *sp);
+		sp->text = start;
+		*arglist->lastp = sp;
+		arglist->lastp = &sp->next;
+		return;
+	}
+
+	ifs = ifsset() ? ifsval() : " \t\n";
+
+	for (ifsp = &ifsfirst; ifsp != NULL; ifsp = ifsp->next) {
+		p = string + ifsp->begoff;
+		while (p < string + ifsp->endoff) {
+			q = p;
+			if (*p == CTLESC)
+				p++;
+			if (ifsp->inquotes) {
+				/* Only NULs (should be from "$@") end args */
+				had_param_ch = 1;
+				if (*p != 0) {
+					p++;
+					continue;
+				}
+				ifsspc = NULL;
+			} else {
+				if (!strchr(ifs, *p)) {
+					had_param_ch = 1;
+					p++;
+					continue;
+				}
+				ifsspc = strchr(" \t\n", *p);
+
+				/* Ignore IFS whitespace at start */
+				if (q == start && ifsspc != NULL) {
+					p++;
+					start = p;
+					continue;
+				}
+				had_param_ch = 0;
+			}
+
+			/* Save this argument... */
+			*q = '\0';
+			sp = (struct strlist *)stalloc(sizeof *sp);
+			sp->text = start;
+			*arglist->lastp = sp;
+			arglist->lastp = &sp->next;
+			p++;
+
+			if (ifsspc != NULL) {
+				/* Ignore further trailing IFS whitespace */
+				for (; p < string + ifsp->endoff; p++) {
+					q = p;
+					if (*p == CTLESC)
+						p++;
+					if (strchr(ifs, *p) == NULL) {
+						p = q;
+						break;
+					}
+					if (strchr(" \t\n", *p) == NULL) {
+						p++;
+						break;
+					}
+				}
+			}
+			start = p;
+		}
+	}
+
+	/*
+	 * Save anything left as an argument.
+	 * Traditionally we have treated 'IFS=':'; set -- x$IFS' as
+	 * generating 2 arguments, the second of which is empty.
+	 * Some recent clarification of the Posix spec say that it
+	 * should only generate one....
+	 */
+	if (had_param_ch || *start != 0) {
+		sp = (struct strlist *)stalloc(sizeof *sp);
+		sp->text = start;
+		*arglist->lastp = sp;
+		arglist->lastp = &sp->next;
+	}
+}
+
+
+static char expdir[PATH_MAX];
+#define expdir_end (expdir + sizeof(expdir))
+
+/*
+ * Perform pathname generation and remove control characters.
+ * At this point, the only control characters should be CTLESC and CTLQUOTEMARK.
+ * The results are stored in the list exparg.
+ */
+static void
+expandmeta(struct strlist *str)
+{
+	char *p;
+	struct strlist **savelastp;
+	struct strlist *sp;
+	char c;
+
+	while (str) {
+		savelastp = exparg.lastp;
+		if (!fflag) {
+			p = str->text;
+			for (; (c = *p) != '\0'; p++) {
+				/* fast check for meta chars */
+				if (c == '*' || c == '?' || c == '[') {
+					INTOFF;
+					expmeta(expdir, str->text);
+					INTON;
+					break;
+				}
+			}
+		}
+		if (exparg.lastp == savelastp) {
+			/*
+			 * no matches
+			 */
+			*exparg.lastp = str;
+			rmescapes(str->text);
+			exparg.lastp = &str->next;
+		} else {
+			*exparg.lastp = NULL;
+			*savelastp = sp = expsort(*savelastp);
+			while (sp->next != NULL)
+				sp = sp->next;
+			exparg.lastp = &sp->next;
+		}
+		str = str->next;
+	}
+}
+
+
+/*
+ * Do metacharacter (i.e. *, ?, [...]) expansion.
+ */
+
+static void
+expmeta(char *enddir, char *name)
+{
+	const char *p;
+	const char *q;
+	const char *start;
+	char *endname;
+	int metaflag;
+	struct stat statb;
+	DIR *dirp;
+	struct dirent *dp;
+	int atend;
+	int matchdot;
+	int esc;
+	int namlen;
+
+	metaflag = 0;
+	start = name;
+	for (p = name; esc = 0, *p; p += esc + 1) {
+		if (*p == '*' || *p == '?')
+			metaflag = 1;
+		else if (*p == '[') {
+			q = p + 1;
+			if (*q == '!' || *q == '^')
+				q++;
+			for (;;) {
+				while (*q == CTLQUOTEMARK)
+					q++;
+				if (*q == CTLESC)
+					q++;
+				if (*q == '/' || *q == '\0')
+					break;
+				if (*++q == ']') {
+					metaflag = 1;
+					break;
+				}
+			}
+		} else if (*p == '\0')
+			break;
+		else if (*p == CTLQUOTEMARK)
+			continue;
+		else {
+			if (*p == CTLESC)
+				esc++;
+			if (p[esc] == '/') {
+				if (metaflag)
+					break;
+				start = p + esc + 1;
+			}
+		}
+	}
+	if (metaflag == 0) {	/* we've reached the end of the file name */
+		if (enddir != expdir)
+			metaflag++;
+		for (p = name ; ; p++) {
+			if (*p == CTLQUOTEMARK)
+				continue;
+			if (*p == CTLESC)
+				p++;
+			*enddir++ = *p;
+			if (*p == '\0')
+				break;
+			if (enddir == expdir_end)
+				return;
+		}
+		if (metaflag == 0 || lstat(expdir, &statb) >= 0)
+			addfname(expdir);
+		return;
+	}
+	endname = name + (p - name);
+	if (start != name) {
+		p = name;
+		while (p < start) {
+			while (*p == CTLQUOTEMARK)
+				p++;
+			if (*p == CTLESC)
+				p++;
+			*enddir++ = *p++;
+			if (enddir == expdir_end)
+				return;
+		}
+	}
+	if (enddir == expdir) {
+		p = ".";
+	} else if (enddir == expdir + 1 && *expdir == '/') {
+		p = "/";
+	} else {
+		p = expdir;
+		enddir[-1] = '\0';
+	}
+	if ((dirp = opendir(p)) == NULL)
+		return;
+	if (enddir != expdir)
+		enddir[-1] = '/';
+	if (*endname == 0) {
+		atend = 1;
+	} else {
+		atend = 0;
+		*endname = '\0';
+		endname += esc + 1;
+	}
+	matchdot = 0;
+	p = start;
+	while (*p == CTLQUOTEMARK)
+		p++;
+	if (*p == CTLESC)
+		p++;
+	if (*p == '.')
+		matchdot++;
+	while (! int_pending() && (dp = readdir(dirp)) != NULL) {
+		if (dp->d_name[0] == '.' && ! matchdot)
+			continue;
+		if (patmatch(start, dp->d_name, 0)) {
+			namlen = dp->d_namlen;
+			if (enddir + namlen + 1 > expdir_end)
+				continue;
+			memcpy(enddir, dp->d_name, namlen + 1);
+			if (atend)
+				addfname(expdir);
+			else {
+				if (dp->d_type != DT_UNKNOWN &&
+				    dp->d_type != DT_DIR &&
+				    dp->d_type != DT_LNK)
+					continue;
+				if (enddir + namlen + 2 > expdir_end)
+					continue;
+				enddir[namlen] = '/';
+				enddir[namlen + 1] = '\0';
+				expmeta(enddir + namlen + 1, endname);
+			}
+		}
+	}
+	closedir(dirp);
+	if (! atend)
+		endname[-esc - 1] = esc ? CTLESC : '/';
+}
+
+
+/*
+ * Add a file name to the list.
+ */
+
+static void
+addfname(char *name)
+{
+	char *p;
+	struct strlist *sp;
+
+	p = stsavestr(name);
+	sp = (struct strlist *)stalloc(sizeof *sp);
+	sp->text = p;
+	*exparg.lastp = sp;
+	exparg.lastp = &sp->next;
+}
+
+
+/*
+ * Sort the results of file name expansion.  It calculates the number of
+ * strings to sort and then calls msort (short for merge sort) to do the
+ * work.
+ */
+
+static struct strlist *
+expsort(struct strlist *str)
+{
+	int len;
+	struct strlist *sp;
+
+	len = 0;
+	for (sp = str ; sp ; sp = sp->next)
+		len++;
+	return msort(str, len);
+}
+
+
+static struct strlist *
+msort(struct strlist *list, int len)
+{
+	struct strlist *p, *q = NULL;
+	struct strlist **lpp;
+	int half;
+	int n;
+
+	if (len <= 1)
+		return list;
+	half = len >> 1;
+	p = list;
+	for (n = half ; --n >= 0 ; ) {
+		q = p;
+		p = p->next;
+	}
+	q->next = NULL;			/* terminate first half of list */
+	q = msort(list, half);		/* sort first half of list */
+	p = msort(p, len - half);		/* sort second half */
+	lpp = &list;
+	for (;;) {
+		if (strcmp(p->text, q->text) < 0) {
+			*lpp = p;
+			lpp = &p->next;
+			if ((p = *lpp) == NULL) {
+				*lpp = q;
+				break;
+			}
+		} else {
+			*lpp = q;
+			lpp = &q->next;
+			if ((q = *lpp) == NULL) {
+				*lpp = p;
+				break;
+			}
+		}
+	}
+	return list;
+}
+
+
+
+static wchar_t
+get_wc(const char **p)
+{
+	wchar_t c;
+	int chrlen;
+
+	chrlen = mbtowc(&c, *p, 4);
+	if (chrlen == 0)
+		return 0;
+	else if (chrlen == -1)
+		c = 0;
+	else
+		*p += chrlen;
+	return c;
+}
+
+
+/*
+ * See if a character matches a character class, starting at the first colon
+ * of "[:class:]".
+ * If a valid character class is recognized, a pointer to the next character
+ * after the final closing bracket is stored into *end, otherwise a null
+ * pointer is stored into *end.
+ */
+static int
+match_charclass(const char *p, wchar_t chr, const char **end)
+{
+	char name[20];
+	const char *nameend;
+	wctype_t cclass;
+
+	*end = NULL;
+	p++;
+	nameend = strstr(p, ":]");
+	if (nameend == NULL || (size_t)(nameend - p) >= sizeof(name) ||
+	    nameend == p)
+		return 0;
+	memcpy(name, p, nameend - p);
+	name[nameend - p] = '\0';
+	*end = nameend + 2;
+	cclass = wctype(name);
+	/* An unknown class matches nothing but is valid nevertheless. */
+	if (cclass == 0)
+		return 0;
+	return iswctype(chr, cclass);
+}
+
+
+/*
+ * Returns true if the pattern matches the string.
+ */
+
+static int
+patmatch(const char *pattern, const char *string, int squoted)
+{
+	const char *p, *q, *end;
+	const char *bt_p, *bt_q;
+	char c;
+	wchar_t wc, wc2;
+
+	p = pattern;
+	q = string;
+	bt_p = NULL;
+	bt_q = NULL;
+	for (;;) {
+		switch (c = *p++) {
+		case '\0':
+			if (*q != '\0')
+				goto backtrack;
+			return 1;
+		case CTLESC:
+			if (squoted && *q == CTLESC)
+				q++;
+			if (*q++ != *p++)
+				goto backtrack;
+			break;
+		case CTLQUOTEMARK:
+			continue;
+		case '?':
+			if (squoted && *q == CTLESC)
+				q++;
+			if (*q == '\0')
+				return 0;
+			if (localeisutf8) {
+				wc = get_wc(&q);
+				/*
+				 * A '?' does not match invalid UTF-8 but a
+				 * '*' does, so backtrack.
+				 */
+				if (wc == 0)
+					goto backtrack;
+			} else
+				wc = (unsigned char)*q++;
+			break;
+		case '*':
+			c = *p;
+			while (c == CTLQUOTEMARK || c == '*')
+				c = *++p;
+			/*
+			 * If the pattern ends here, we know the string
+			 * matches without needing to look at the rest of it.
+			 */
+			if (c == '\0')
+				return 1;
+			/*
+			 * First try the shortest match for the '*' that
+			 * could work. We can forget any earlier '*' since
+			 * there is no way having it match more characters
+			 * can help us, given that we are already here.
+			 */
+			bt_p = p;
+			bt_q = q;
+			break;
+		case '[': {
+			const char *endp;
+			int invert, found;
+			wchar_t chr;
+
+			endp = p;
+			if (*endp == '!' || *endp == '^')
+				endp++;
+			do {
+				while (*endp == CTLQUOTEMARK)
+					endp++;
+				if (*endp == 0)
+					goto dft;		/* no matching ] */
+				if (*endp == CTLESC)
+					endp++;
+			} while (*++endp != ']');
+			invert = 0;
+			if (*p == '!' || *p == '^') {
+				invert++;
+				p++;
+			}
+			found = 0;
+			if (squoted && *q == CTLESC)
+				q++;
+			if (*q == '\0')
+				return 0;
+			if (localeisutf8) {
+				chr = get_wc(&q);
+				if (chr == 0)
+					goto backtrack;
+			} else
+				chr = (unsigned char)*q++;
+			c = *p++;
+			do {
+				if (c == CTLQUOTEMARK)
+					continue;
+				if (c == '[' && *p == ':') {
+					found |= match_charclass(p, chr, &end);
+					if (end != NULL)
+						p = end;
+				}
+				if (c == CTLESC)
+					c = *p++;
+				if (localeisutf8 && c & 0x80) {
+					p--;
+					wc = get_wc(&p);
+					if (wc == 0) /* bad utf-8 */
+						return 0;
+				} else
+					wc = (unsigned char)c;
+				if (*p == '-' && p[1] != ']') {
+					p++;
+					while (*p == CTLQUOTEMARK)
+						p++;
+					if (*p == CTLESC)
+						p++;
+					if (localeisutf8) {
+						wc2 = get_wc(&p);
+						if (wc2 == 0) /* bad utf-8 */
+							return 0;
+					} else
+						wc2 = (unsigned char)*p++;
+					if (   collate_range_cmp(chr, wc) >= 0
+					    && collate_range_cmp(chr, wc2) <= 0
+					   )
+						found = 1;
+				} else {
+					if (chr == wc)
+						found = 1;
+				}
+			} while ((c = *p++) != ']');
+			if (found == invert)
+				goto backtrack;
+			break;
+		}
+dft:	        default:
+			if (squoted && *q == CTLESC)
+				q++;
+			if (*q == '\0')
+				return 0;
+			if (*q++ == c)
+				break;
+backtrack:
+			/*
+			 * If we have a mismatch (other than hitting the end
+			 * of the string), go back to the last '*' seen and
+			 * have it match one additional character.
+			 */
+			if (bt_p == NULL)
+				return 0;
+			if (squoted && *bt_q == CTLESC)
+				bt_q++;
+			if (*bt_q == '\0')
+				return 0;
+			bt_q++;
+			p = bt_p;
+			q = bt_q;
+			break;
+		}
+	}
+}
+
+
+
+/*
+ * Remove any CTLESC and CTLQUOTEMARK characters from a string.
+ */
+
+void
+rmescapes(char *str)
+{
+	char *p, *q;
+
+	p = str;
+	while (*p != CTLESC && *p != CTLQUOTEMARK && *p != CTLQUOTEEND) {
+		if (*p++ == '\0')
+			return;
+	}
+	q = p;
+	while (*p) {
+		if (*p == CTLQUOTEMARK || *p == CTLQUOTEEND) {
+			p++;
+			continue;
+		}
+		if (*p == CTLESC)
+			p++;
+		*q++ = *p++;
+	}
+	*q = '\0';
+}
+
+
+
+/*
+ * See if a pattern matches in a case statement.
+ */
+
+int
+casematch(union node *pattern, const char *val)
+{
+	struct stackmark smark;
+	int result;
+	char *p;
+
+	setstackmark(&smark);
+	argbackq = pattern->narg.backquote;
+	STARTSTACKSTR(expdest);
+	ifslastp = NULL;
+	argstr(pattern->narg.text, EXP_TILDE | EXP_CASE);
+	STPUTC('\0', expdest);
+	p = grabstackstr(expdest);
+	result = patmatch(p, val, 0);
+	popstackmark(&smark);
+	return result;
+}
+
+/*
+ * Our own itoa().
+ */
+
+static char *
+cvtnum(int num, char *buf)
+{
+	char temp[32];
+	int neg = num < 0;
+	char *p = temp + 31;
+
+	temp[31] = '\0';
+
+	do {
+		*--p = num % 10 + '0';
+	} while ((num /= 10) != 0);
+
+	if (neg)
+		*--p = '-';
+
+	STPUTS(p, buf);
+	return buf;
+}
+
+/*
+ * Do most of the work for wordexp(3).
+ */
+
+int
+wordexpcmd(int argc, char **argv)
+{
+	size_t len;
+	int i;
+
+	out1fmt("%08x", argc - 1);
+	for (i = 1, len = 0; i < argc; i++)
+		len += strlen(argv[i]);
+	out1fmt("%08x", (int)len);
+	for (i = 1; i < argc; i++)
+		outbin(argv[i], strlen(argv[i]) + 1, out1);
+        return (0);
+}
diff --git a/external/sh/expand.h b/external/sh/expand.h
new file mode 100644
index 00000000..2da855d2
--- /dev/null
+++ b/external/sh/expand.h
@@ -0,0 +1,61 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)expand.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: head/bin/sh/expand.h 276037 2014-12-21 22:18:30Z jilles $
+ */
+
+struct strlist {
+	struct strlist *next;
+	char *text;
+};
+
+
+struct arglist {
+	struct strlist *list;
+	struct strlist **lastp;
+};
+
+/*
+ * expandarg() flags
+ */
+#define EXP_FULL	0x1	/* perform word splitting & file globbing */
+#define EXP_TILDE	0x2	/* do normal tilde expansion */
+#define	EXP_VARTILDE	0x4	/* expand tildes in an assignment */
+#define EXP_CASE	0x10	/* keeps quotes around for CASE pattern */
+#define EXP_SPLIT_LIT	0x20	/* IFS split literal text ${v+-a b c} */
+#define EXP_LIT_QUOTED	0x40	/* for EXP_SPLIT_LIT, start off quoted */
+
+
+union node;
+void expandarg(union node *, struct arglist *, int);
+void rmescapes(char *);
+int casematch(union node *, const char *);
diff --git a/external/sh/histedit.c b/external/sh/histedit.c
new file mode 100644
index 00000000..dad46722
--- /dev/null
+++ b/external/sh/histedit.c
@@ -0,0 +1,502 @@
+/*-
+ * Copyright (c) 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)histedit.c	8.2 (Berkeley) 5/4/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: head/bin/sh/histedit.c 279508 2015-03-01 22:32:23Z jilles $");
+
+#include <sys/param.h>
+#include <limits.h>
+#include <paths.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+/*
+ * Editline and history functions (and glue).
+ */
+#include "shell.h"
+#include "parser.h"
+#include "var.h"
+#include "options.h"
+#include "main.h"
+#include "output.h"
+#include "mystring.h"
+#ifndef NO_HISTORY
+#include "myhistedit.h"
+#include "error.h"
+#include "eval.h"
+#include "memalloc.h"
+#include "builtins.h"
+
+#define MAXHISTLOOPS	4	/* max recursions through fc */
+#define DEFEDITOR	"ed"	/* default editor *should* be $EDITOR */
+
+History *hist;	/* history cookie */
+EditLine *el;	/* editline cookie */
+int displayhist;
+static FILE *el_in, *el_out, *el_err;
+
+static char *fc_replace(const char *, char *, char *);
+static int not_fcnumber(const char *);
+static int str_to_event(const char *, int);
+
+/*
+ * Set history and editing status.  Called whenever the status may
+ * have changed (figures out what to do).
+ */
+void
+histedit(void)
+{
+
+#define editing (Eflag || Vflag)
+
+	if (iflag) {
+		if (!hist) {
+			/*
+			 * turn history on
+			 */
+			INTOFF;
+			hist = history_init();
+			INTON;
+
+			if (hist != NULL)
+				sethistsize(histsizeval());
+			else
+				out2fmt_flush("sh: can't initialize history\n");
+		}
+		if (editing && !el && isatty(0)) { /* && isatty(2) ??? */
+			/*
+			 * turn editing on
+			 */
+			char *term;
+
+			INTOFF;
+			if (el_in == NULL)
+				el_in = fdopen(0, "r");
+			if (el_err == NULL)
+				el_err = fdopen(1, "w");
+			if (el_out == NULL)
+				el_out = fdopen(2, "w");
+			if (el_in == NULL || el_err == NULL || el_out == NULL)
+				goto bad;
+			term = lookupvar("TERM");
+			if (term)
+				setenv("TERM", term, 1);
+			else
+				unsetenv("TERM");
+			el = el_init(arg0, el_in, el_out, el_err);
+			if (el != NULL) {
+				if (hist)
+					el_set(el, EL_HIST, history, hist);
+				el_set(el, EL_PROMPT, getprompt);
+				el_set(el, EL_ADDFN, "sh-complete",
+				    "Filename completion",
+				    _el_fn_sh_complete);
+			} else {
+bad:
+				out2fmt_flush("sh: can't initialize editing\n");
+			}
+			INTON;
+		} else if (!editing && el) {
+			INTOFF;
+			el_end(el);
+			el = NULL;
+			INTON;
+		}
+		if (el) {
+			if (Vflag)
+				el_set(el, EL_EDITOR, "vi");
+			else if (Eflag)
+				el_set(el, EL_EDITOR, "emacs");
+			el_set(el, EL_BIND, "^I", "sh-complete", NULL);
+			el_source(el, NULL);
+		}
+	} else {
+		INTOFF;
+		if (el) {	/* no editing if not interactive */
+			el_end(el);
+			el = NULL;
+		}
+		if (hist) {
+			history_end(hist);
+			hist = NULL;
+		}
+		INTON;
+	}
+}
+
+
+void
+sethistsize(const char *hs)
+{
+	int histsize;
+	HistEvent he;
+
+	if (hist != NULL) {
+		if (hs == NULL || !is_number(hs))
+			histsize = 100;
+		else
+			histsize = atoi(hs);
+		history(hist, &he, H_SETSIZE, histsize);
+		history(hist, &he, H_SETUNIQUE, 1);
+	}
+}
+
+void
+setterm(const char *term)
+{
+	if (rootshell && el != NULL && term != NULL)
+		el_set(el, EL_TERMINAL, term);
+}
+
+int
+histcmd(int argc, char **argv __unused)
+{
+	int ch;
+	const char *editor = NULL;
+	HistEvent he;
+	int lflg = 0, nflg = 0, rflg = 0, sflg = 0;
+	int i, retval;
+	const char *firststr, *laststr;
+	int first, last, direction;
+	char *pat = NULL, *repl = NULL;
+	static int active = 0;
+	struct jmploc jmploc;
+	struct jmploc *savehandler;
+	char editfilestr[PATH_MAX];
+	char *volatile editfile;
+	FILE *efp = NULL;
+	int oldhistnum;
+
+	if (hist == NULL)
+		error("history not active");
+
+	if (argc == 1)
+		error("missing history argument");
+
+	while (not_fcnumber(*argptr) && (ch = nextopt("e:lnrs")) != '\0')
+		switch ((char)ch) {
+		case 'e':
+			editor = shoptarg;
+			break;
+		case 'l':
+			lflg = 1;
+			break;
+		case 'n':
+			nflg = 1;
+			break;
+		case 'r':
+			rflg = 1;
+			break;
+		case 's':
+			sflg = 1;
+			break;
+		}
+
+	savehandler = handler;
+	/*
+	 * If executing...
+	 */
+	if (lflg == 0 || editor || sflg) {
+		lflg = 0;	/* ignore */
+		editfile = NULL;
+		/*
+		 * Catch interrupts to reset active counter and
+		 * cleanup temp files.
+		 */
+		if (setjmp(jmploc.loc)) {
+			active = 0;
+			if (editfile)
+				unlink(editfile);
+			handler = savehandler;
+			longjmp(handler->loc, 1);
+		}
+		handler = &jmploc;
+		if (++active > MAXHISTLOOPS) {
+			active = 0;
+			displayhist = 0;
+			error("called recursively too many times");
+		}
+		/*
+		 * Set editor.
+		 */
+		if (sflg == 0) {
+			if (editor == NULL &&
+			    (editor = bltinlookup("FCEDIT", 1)) == NULL &&
+			    (editor = bltinlookup("EDITOR", 1)) == NULL)
+				editor = DEFEDITOR;
+			if (editor[0] == '-' && editor[1] == '\0') {
+				sflg = 1;	/* no edit */
+				editor = NULL;
+			}
+		}
+	}
+
+	/*
+	 * If executing, parse [old=new] now
+	 */
+	if (lflg == 0 && *argptr != NULL &&
+	     ((repl = strchr(*argptr, '=')) != NULL)) {
+		pat = *argptr;
+		*repl++ = '\0';
+		argptr++;
+	}
+	/*
+	 * determine [first] and [last]
+	 */
+	if (*argptr == NULL) {
+		firststr = lflg ? "-16" : "-1";
+		laststr = "-1";
+	} else if (argptr[1] == NULL) {
+		firststr = argptr[0];
+		laststr = lflg ? "-1" : argptr[0];
+	} else if (argptr[2] == NULL) {
+		firststr = argptr[0];
+		laststr = argptr[1];
+	} else
+		error("too many arguments");
+	/*
+	 * Turn into event numbers.
+	 */
+	first = str_to_event(firststr, 0);
+	last = str_to_event(laststr, 1);
+
+	if (rflg) {
+		i = last;
+		last = first;
+		first = i;
+	}
+	/*
+	 * XXX - this should not depend on the event numbers
+	 * always increasing.  Add sequence numbers or offset
+	 * to the history element in next (diskbased) release.
+	 */
+	direction = first < last ? H_PREV : H_NEXT;
+
+	/*
+	 * If editing, grab a temp file.
+	 */
+	if (editor) {
+		int fd;
+		INTOFF;		/* easier */
+		sprintf(editfilestr, "%s/_shXXXXXX", _PATH_TMP);
+		if ((fd = mkstemp(editfilestr)) < 0)
+			error("can't create temporary file %s", editfile);
+		editfile = editfilestr;
+		if ((efp = fdopen(fd, "w")) == NULL) {
+			close(fd);
+			error("Out of space");
+		}
+	}
+
+	/*
+	 * Loop through selected history events.  If listing or executing,
+	 * do it now.  Otherwise, put into temp file and call the editor
+	 * after.
+	 *
+	 * The history interface needs rethinking, as the following
+	 * convolutions will demonstrate.
+	 */
+	history(hist, &he, H_FIRST);
+	retval = history(hist, &he, H_NEXT_EVENT, first);
+	for (;retval != -1; retval = history(hist, &he, direction)) {
+		if (lflg) {
+			if (!nflg)
+				out1fmt("%5d ", he.num);
+			out1str(he.str);
+		} else {
+			const char *s = pat ?
+			   fc_replace(he.str, pat, repl) : he.str;
+
+			if (sflg) {
+				if (displayhist) {
+					out2str(s);
+					flushout(out2);
+				}
+				evalstring(s, 0);
+				if (displayhist && hist) {
+					/*
+					 *  XXX what about recursive and
+					 *  relative histnums.
+					 */
+					oldhistnum = he.num;
+					history(hist, &he, H_ENTER, s);
+					/*
+					 * XXX H_ENTER moves the internal
+					 * cursor, set it back to the current
+					 * entry.
+					 */
+					retval = history(hist, &he,
+					    H_NEXT_EVENT, oldhistnum);
+				}
+			} else
+				fputs(s, efp);
+		}
+		/*
+		 * At end?  (if we were to lose last, we'd sure be
+		 * messed up).
+		 */
+		if (he.num == last)
+			break;
+	}
+	if (editor) {
+		char *editcmd;
+
+		fclose(efp);
+		editcmd = stalloc(strlen(editor) + strlen(editfile) + 2);
+		sprintf(editcmd, "%s %s", editor, editfile);
+		evalstring(editcmd, 0);	/* XXX - should use no JC command */
+		INTON;
+		readcmdfile(editfile);	/* XXX - should read back - quick tst */
+		unlink(editfile);
+	}
+
+	if (lflg == 0 && active > 0)
+		--active;
+	if (displayhist)
+		displayhist = 0;
+	handler = savehandler;
+	return 0;
+}
+
+static char *
+fc_replace(const char *s, char *p, char *r)
+{
+	char *dest;
+	int plen = strlen(p);
+
+	STARTSTACKSTR(dest);
+	while (*s) {
+		if (*s == *p && strncmp(s, p, plen) == 0) {
+			STPUTS(r, dest);
+			s += plen;
+			*p = '\0';	/* so no more matches */
+		} else
+			STPUTC(*s++, dest);
+	}
+	STPUTC('\0', dest);
+	dest = grabstackstr(dest);
+
+	return (dest);
+}
+
+static int
+not_fcnumber(const char *s)
+{
+	if (s == NULL)
+		return (0);
+	if (*s == '-')
+		s++;
+	return (!is_number(s));
+}
+
+static int
+str_to_event(const char *str, int last)
+{
+	HistEvent he;
+	const char *s = str;
+	int relative = 0;
+	int i, retval;
+
+	retval = history(hist, &he, H_FIRST);
+	switch (*s) {
+	case '-':
+		relative = 1;
+		/*FALLTHROUGH*/
+	case '+':
+		s++;
+	}
+	if (is_number(s)) {
+		i = atoi(s);
+		if (relative) {
+			while (retval != -1 && i--) {
+				retval = history(hist, &he, H_NEXT);
+			}
+			if (retval == -1)
+				retval = history(hist, &he, H_LAST);
+		} else {
+			retval = history(hist, &he, H_NEXT_EVENT, i);
+			if (retval == -1) {
+				/*
+				 * the notion of first and last is
+				 * backwards to that of the history package
+				 */
+				retval = history(hist, &he, last ? H_FIRST : H_LAST);
+			}
+		}
+		if (retval == -1)
+			error("history number %s not found (internal error)",
+			       str);
+	} else {
+		/*
+		 * pattern
+		 */
+		retval = history(hist, &he, H_PREV_STR, str);
+		if (retval == -1)
+			error("history pattern not found: %s", str);
+	}
+	return (he.num);
+}
+
+int
+bindcmd(int argc, char **argv)
+{
+
+	if (el == NULL)
+		error("line editing is disabled");
+	return (el_parse(el, argc, __DECONST(const char **, argv)));
+}
+
+#else
+#include "error.h"
+
+int
+histcmd(int argc, char **argv)
+{
+
+	error("not compiled with history support");
+	/*NOTREACHED*/
+	return (0);
+}
+
+int
+bindcmd(int argc, char **argv)
+{
+
+	error("not compiled with line editing support");
+	return (0);
+}
+#endif
diff --git a/external/sh/input.c b/external/sh/input.c
new file mode 100644
index 00000000..aeb3590e
--- /dev/null
+++ b/external/sh/input.c
@@ -0,0 +1,523 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)input.c	8.3 (Berkeley) 6/9/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: head/bin/sh/input.c 271593 2014-09-14 16:46:30Z jilles $");
+
+#include <stdio.h>	/* defines BUFSIZ */
+#include <fcntl.h>
+#include <errno.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+
+/*
+ * This file implements the input routines used by the parser.
+ */
+
+#include "shell.h"
+#include "redir.h"
+#include "syntax.h"
+#include "input.h"
+#include "output.h"
+#include "options.h"
+#include "memalloc.h"
+#include "error.h"
+#include "alias.h"
+#include "parser.h"
+#include "myhistedit.h"
+#include "trap.h"
+
+#define EOF_NLEFT -99		/* value of parsenleft when EOF pushed back */
+
+struct strpush {
+	struct strpush *prev;	/* preceding string on stack */
+	const char *prevstring;
+	int prevnleft;
+	int prevlleft;
+	struct alias *ap;	/* if push was associated with an alias */
+};
+
+/*
+ * The parsefile structure pointed to by the global variable parsefile
+ * contains information about the current file being read.
+ */
+
+struct parsefile {
+	struct parsefile *prev;	/* preceding file on stack */
+	int linno;		/* current line */
+	int fd;			/* file descriptor (or -1 if string) */
+	int nleft;		/* number of chars left in this line */
+	int lleft;		/* number of lines left in this buffer */
+	const char *nextc;	/* next char in buffer */
+	char *buf;		/* input buffer */
+	struct strpush *strpush; /* for pushing strings at this level */
+	struct strpush basestrpush; /* so pushing one is fast */
+};
+
+
+int plinno = 1;			/* input line number */
+int parsenleft;			/* copy of parsefile->nleft */
+static int parselleft;		/* copy of parsefile->lleft */
+const char *parsenextc;		/* copy of parsefile->nextc */
+static char basebuf[BUFSIZ + 1];/* buffer for top level input file */
+static struct parsefile basepf = {	/* top level input file */
+	.nextc = basebuf,
+	.buf = basebuf
+};
+static struct parsefile *parsefile = &basepf;	/* current input file */
+int whichprompt;		/* 1 == PS1, 2 == PS2 */
+
+EditLine *el;			/* cookie for editline package */
+
+static void pushfile(void);
+static int preadfd(void);
+static void popstring(void);
+
+void
+resetinput(void)
+{
+	popallfiles();
+	parselleft = parsenleft = 0;	/* clear input buffer */
+}
+
+
+
+/*
+ * Read a character from the script, returning PEOF on end of file.
+ * Nul characters in the input are silently discarded.
+ */
+
+int
+pgetc(void)
+{
+	return pgetc_macro();
+}
+
+
+static int
+preadfd(void)
+{
+	int nr;
+	parsenextc = parsefile->buf;
+
+retry:
+#ifndef NO_HISTORY
+	if (parsefile->fd == 0 && el) {
+		static const char *rl_cp;
+		static int el_len;
+
+		if (rl_cp == NULL) {
+			el_resize(el);
+			rl_cp = el_gets(el, &el_len);
+		}
+		if (rl_cp == NULL)
+			nr = el_len == 0 ? 0 : -1;
+		else {
+			nr = el_len;
+			if (nr > BUFSIZ)
+				nr = BUFSIZ;
+			memcpy(parsefile->buf, rl_cp, nr);
+			if (nr != el_len) {
+				el_len -= nr;
+				rl_cp += nr;
+			} else
+				rl_cp = NULL;
+		}
+	} else
+#endif
+		nr = read(parsefile->fd, parsefile->buf, BUFSIZ);
+
+	if (nr <= 0) {
+                if (nr < 0) {
+                        if (errno == EINTR)
+                                goto retry;
+                        if (parsefile->fd == 0 && errno == EWOULDBLOCK) {
+                                int flags = fcntl(0, F_GETFL, 0);
+                                if (flags >= 0 && flags & O_NONBLOCK) {
+                                        flags &=~ O_NONBLOCK;
+                                        if (fcntl(0, F_SETFL, flags) >= 0) {
+						out2fmt_flush("sh: turning off NDELAY mode\n");
+                                                goto retry;
+                                        }
+                                }
+                        }
+                }
+                nr = -1;
+	}
+	return nr;
+}
+
+/*
+ * Refill the input buffer and return the next input character:
+ *
+ * 1) If a string was pushed back on the input, pop it;
+ * 2) If an EOF was pushed back (parsenleft == EOF_NLEFT) or we are reading
+ *    from a string so we can't refill the buffer, return EOF.
+ * 3) If there is more in this buffer, use it else call read to fill it.
+ * 4) Process input up to the next newline, deleting nul characters.
+ */
+
+int
+preadbuffer(void)
+{
+	char *p, *q;
+	int more;
+	char savec;
+
+	while (parsefile->strpush) {
+		/*
+		 * Add a space to the end of an alias to ensure that the
+		 * alias remains in use while parsing its last word.
+		 * This avoids alias recursions.
+		 */
+		if (parsenleft == -1 && parsefile->strpush->ap != NULL)
+			return ' ';
+		popstring();
+		if (--parsenleft >= 0)
+			return (*parsenextc++);
+	}
+	if (parsenleft == EOF_NLEFT || parsefile->buf == NULL)
+		return PEOF;
+	flushout(&output);
+	flushout(&errout);
+
+again:
+	if (parselleft <= 0) {
+		if ((parselleft = preadfd()) == -1) {
+			parselleft = parsenleft = EOF_NLEFT;
+			return PEOF;
+		}
+	}
+
+	q = p = parsefile->buf + (parsenextc - parsefile->buf);
+
+	/* delete nul characters */
+	for (more = 1; more;) {
+		switch (*p) {
+		case '\0':
+			p++;	/* Skip nul */
+			goto check;
+
+		case '\n':
+			parsenleft = q - parsenextc;
+			more = 0; /* Stop processing here */
+			break;
+
+		default:
+			break;
+		}
+
+		*q++ = *p++;
+check:
+		if (--parselleft <= 0) {
+			parsenleft = q - parsenextc - 1;
+			if (parsenleft < 0)
+				goto again;
+			*q = '\0';
+			more = 0;
+		}
+	}
+
+	savec = *q;
+	*q = '\0';
+
+#ifndef NO_HISTORY
+	if (parsefile->fd == 0 && hist &&
+	    parsenextc[strspn(parsenextc, " \t\n")] != '\0') {
+		HistEvent he;
+		INTOFF;
+		history(hist, &he, whichprompt == 1 ? H_ENTER : H_ADD,
+		    parsenextc);
+		INTON;
+	}
+#endif
+
+	if (vflag) {
+		out2str(parsenextc);
+		flushout(out2);
+	}
+
+	*q = savec;
+
+	return *parsenextc++;
+}
+
+/*
+ * Returns if we are certain we are at EOF. Does not cause any more input
+ * to be read from the outside world.
+ */
+
+int
+preadateof(void)
+{
+	if (parsenleft > 0)
+		return 0;
+	if (parsefile->strpush)
+		return 0;
+	if (parsenleft == EOF_NLEFT || parsefile->buf == NULL)
+		return 1;
+	return 0;
+}
+
+/*
+ * Undo the last call to pgetc.  Only one character may be pushed back.
+ * PEOF may be pushed back.
+ */
+
+void
+pungetc(void)
+{
+	parsenleft++;
+	parsenextc--;
+}
+
+/*
+ * Push a string back onto the input at this current parsefile level.
+ * We handle aliases this way.
+ */
+void
+pushstring(const char *s, int len, struct alias *ap)
+{
+	struct strpush *sp;
+
+	INTOFF;
+/*out2fmt_flush("*** calling pushstring: %s, %d\n", s, len);*/
+	if (parsefile->strpush) {
+		sp = ckmalloc(sizeof (struct strpush));
+		sp->prev = parsefile->strpush;
+		parsefile->strpush = sp;
+	} else
+		sp = parsefile->strpush = &(parsefile->basestrpush);
+	sp->prevstring = parsenextc;
+	sp->prevnleft = parsenleft;
+	sp->prevlleft = parselleft;
+	sp->ap = ap;
+	if (ap)
+		ap->flag |= ALIASINUSE;
+	parsenextc = s;
+	parsenleft = len;
+	INTON;
+}
+
+static void
+popstring(void)
+{
+	struct strpush *sp = parsefile->strpush;
+
+	INTOFF;
+	if (sp->ap) {
+		if (parsenextc != sp->ap->val &&
+		    (parsenextc[-1] == ' ' || parsenextc[-1] == '\t'))
+			forcealias();
+		sp->ap->flag &= ~ALIASINUSE;
+	}
+	parsenextc = sp->prevstring;
+	parsenleft = sp->prevnleft;
+	parselleft = sp->prevlleft;
+/*out2fmt_flush("*** calling popstring: restoring to '%s'\n", parsenextc);*/
+	parsefile->strpush = sp->prev;
+	if (sp != &(parsefile->basestrpush))
+		ckfree(sp);
+	INTON;
+}
+
+/*
+ * Set the input to take input from a file.  If push is set, push the
+ * old input onto the stack first.
+ */
+
+void
+setinputfile(const char *fname, int push)
+{
+	int fd;
+	int fd2;
+
+	INTOFF;
+	if ((fd = open(fname, O_RDONLY | O_CLOEXEC)) < 0)
+		error("cannot open %s: %s", fname, strerror(errno));
+	if (fd < 10) {
+		fd2 = fcntl(fd, F_DUPFD_CLOEXEC, 10);
+		close(fd);
+		if (fd2 < 0)
+			error("Out of file descriptors");
+		fd = fd2;
+	}
+	setinputfd(fd, push);
+	INTON;
+}
+
+
+/*
+ * Like setinputfile, but takes an open file descriptor (which should have
+ * its FD_CLOEXEC flag already set).  Call this with interrupts off.
+ */
+
+void
+setinputfd(int fd, int push)
+{
+	if (push) {
+		pushfile();
+		parsefile->buf = ckmalloc(BUFSIZ + 1);
+	}
+	if (parsefile->fd > 0)
+		close(parsefile->fd);
+	parsefile->fd = fd;
+	if (parsefile->buf == NULL)
+		parsefile->buf = ckmalloc(BUFSIZ + 1);
+	parselleft = parsenleft = 0;
+	plinno = 1;
+}
+
+
+/*
+ * Like setinputfile, but takes input from a string.
+ */
+
+void
+setinputstring(const char *string, int push)
+{
+	INTOFF;
+	if (push)
+		pushfile();
+	parsenextc = string;
+	parselleft = parsenleft = strlen(string);
+	parsefile->buf = NULL;
+	plinno = 1;
+	INTON;
+}
+
+
+
+/*
+ * To handle the "." command, a stack of input files is used.  Pushfile
+ * adds a new entry to the stack and popfile restores the previous level.
+ */
+
+static void
+pushfile(void)
+{
+	struct parsefile *pf;
+
+	parsefile->nleft = parsenleft;
+	parsefile->lleft = parselleft;
+	parsefile->nextc = parsenextc;
+	parsefile->linno = plinno;
+	pf = (struct parsefile *)ckmalloc(sizeof (struct parsefile));
+	pf->prev = parsefile;
+	pf->fd = -1;
+	pf->strpush = NULL;
+	pf->basestrpush.prev = NULL;
+	parsefile = pf;
+}
+
+
+void
+popfile(void)
+{
+	struct parsefile *pf = parsefile;
+
+	INTOFF;
+	if (pf->fd >= 0)
+		close(pf->fd);
+	if (pf->buf)
+		ckfree(pf->buf);
+	while (pf->strpush)
+		popstring();
+	parsefile = pf->prev;
+	ckfree(pf);
+	parsenleft = parsefile->nleft;
+	parselleft = parsefile->lleft;
+	parsenextc = parsefile->nextc;
+	plinno = parsefile->linno;
+	INTON;
+}
+
+
+/*
+ * Return current file (to go back to it later using popfilesupto()).
+ */
+
+struct parsefile *
+getcurrentfile(void)
+{
+	return parsefile;
+}
+
+
+/*
+ * Pop files until the given file is on top again. Useful for regular
+ * builtins that read shell commands from files or strings.
+ * If the given file is not an active file, an error is raised.
+ */
+
+void
+popfilesupto(struct parsefile *file)
+{
+	while (parsefile != file && parsefile != &basepf)
+		popfile();
+	if (parsefile != file)
+		error("popfilesupto() misused");
+}
+
+/*
+ * Return to top level.
+ */
+
+void
+popallfiles(void)
+{
+	while (parsefile != &basepf)
+		popfile();
+}
+
+
+
+/*
+ * Close the file(s) that the shell is reading commands from.  Called
+ * after a fork is done.
+ */
+
+void
+closescript(void)
+{
+	popallfiles();
+	if (parsefile->fd > 0) {
+		close(parsefile->fd);
+		parsefile->fd = 0;
+	}
+}
diff --git a/external/sh/input.h b/external/sh/input.h
new file mode 100644
index 00000000..1c3ece96
--- /dev/null
+++ b/external/sh/input.h
@@ -0,0 +1,65 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)input.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: head/bin/sh/input.h 271593 2014-09-14 16:46:30Z jilles $
+ */
+
+/* PEOF (the end of file marker) is defined in syntax.h */
+
+/*
+ * The input line number.  Input.c just defines this variable, and saves
+ * and restores it when files are pushed and popped.  The user of this
+ * package must set its value.
+ */
+extern int plinno;
+extern int parsenleft;		/* number of characters left in input buffer */
+extern const char *parsenextc;	/* next character in input buffer */
+
+struct alias;
+struct parsefile;
+
+void resetinput(void);
+int pgetc(void);
+int preadbuffer(void);
+int preadateof(void);
+void pungetc(void);
+void pushstring(const char *, int, struct alias *);
+void setinputfile(const char *, int);
+void setinputfd(int, int);
+void setinputstring(const char *, int);
+void popfile(void);
+struct parsefile *getcurrentfile(void);
+void popfilesupto(struct parsefile *);
+void popallfiles(void);
+void closescript(void);
+
+#define pgetc_macro()	(--parsenleft >= 0? *parsenextc++ : preadbuffer())
diff --git a/external/sh/jobs.c b/external/sh/jobs.c
new file mode 100644
index 00000000..fa796fad
--- /dev/null
+++ b/external/sh/jobs.c
@@ -0,0 +1,1515 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)jobs.c	8.5 (Berkeley) 5/4/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: head/bin/sh/jobs.c 279508 2015-03-01 22:32:23Z jilles $");
+
+#include <sys/ioctl.h>
+#include <sys/param.h>
+#include <sys/resource.h>
+#include <sys/time.h>
+#include <sys/wait.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <paths.h>
+#include <signal.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "shell.h"
+#if JOBS
+#include <termios.h>
+#undef CEOF			/* syntax.h redefines this */
+#endif
+#include "redir.h"
+#include "exec.h"
+#include "show.h"
+#include "main.h"
+#include "parser.h"
+#include "nodes.h"
+#include "jobs.h"
+#include "options.h"
+#include "trap.h"
+#include "syntax.h"
+#include "input.h"
+#include "output.h"
+#include "memalloc.h"
+#include "error.h"
+#include "mystring.h"
+#include "var.h"
+#include "builtins.h"
+
+
+static struct job *jobtab;	/* array of jobs */
+static int njobs;		/* size of array */
+static pid_t backgndpid = -1;	/* pid of last background process */
+static struct job *bgjob = NULL; /* last background process */
+#if JOBS
+static struct job *jobmru;	/* most recently used job list */
+static pid_t initialpgrp;	/* pgrp of shell on invocation */
+#endif
+static int ttyfd = -1;
+
+/* mode flags for dowait */
+#define DOWAIT_BLOCK	0x1 /* wait until a child exits */
+#define DOWAIT_SIG	0x2 /* if DOWAIT_BLOCK, abort on signal */
+#define DOWAIT_SIG_TRAP	0x4 /* if DOWAIT_SIG, abort on trapped signal only */
+
+#if JOBS
+static void restartjob(struct job *);
+#endif
+static void freejob(struct job *);
+static int waitcmdloop(struct job *);
+static struct job *getjob_nonotfound(const char *);
+static struct job *getjob(const char *);
+pid_t killjob(const char *, int);
+static pid_t dowait(int, struct job *);
+static void checkzombies(void);
+static void cmdtxt(union node *);
+static void cmdputs(const char *);
+#if JOBS
+static void setcurjob(struct job *);
+static void deljob(struct job *);
+static struct job *getcurjob(struct job *);
+#endif
+static void printjobcmd(struct job *);
+static void showjob(struct job *, int);
+
+
+/*
+ * Turn job control on and off.
+ */
+
+static int jobctl;
+
+#if JOBS
+static void
+jobctl_notty(void)
+{
+	if (ttyfd >= 0) {
+		close(ttyfd);
+		ttyfd = -1;
+	}
+	if (!iflag) {
+		setsignal(SIGTSTP);
+		setsignal(SIGTTOU);
+		setsignal(SIGTTIN);
+		jobctl = 1;
+		return;
+	}
+	out2fmt_flush("sh: can't access tty; job control turned off\n");
+	mflag = 0;
+}
+
+void
+setjobctl(int on)
+{
+	int i;
+
+	if (on == jobctl || rootshell == 0)
+		return;
+	if (on) {
+		if (ttyfd != -1)
+			close(ttyfd);
+		if ((ttyfd = open(_PATH_TTY, O_RDWR | O_CLOEXEC)) < 0) {
+			i = 0;
+			while (i <= 2 && !isatty(i))
+				i++;
+			if (i > 2 ||
+			    (ttyfd = fcntl(i, F_DUPFD_CLOEXEC, 10)) < 0) {
+				jobctl_notty();
+				return;
+			}
+		}
+		if (ttyfd < 10) {
+			/*
+			 * Keep our TTY file descriptor out of the way of
+			 * the user's redirections.
+			 */
+			if ((i = fcntl(ttyfd, F_DUPFD_CLOEXEC, 10)) < 0) {
+				jobctl_notty();
+				return;
+			}
+			close(ttyfd);
+			ttyfd = i;
+		}
+		do { /* while we are in the background */
+			initialpgrp = tcgetpgrp(ttyfd);
+			if (initialpgrp < 0) {
+				jobctl_notty();
+				return;
+			}
+			if (initialpgrp != getpgrp()) {
+				if (!iflag) {
+					initialpgrp = -1;
+					jobctl_notty();
+					return;
+				}
+				kill(0, SIGTTIN);
+				continue;
+			}
+		} while (0);
+		setsignal(SIGTSTP);
+		setsignal(SIGTTOU);
+		setsignal(SIGTTIN);
+		setpgid(0, rootpid);
+		tcsetpgrp(ttyfd, rootpid);
+	} else { /* turning job control off */
+		setpgid(0, initialpgrp);
+		if (ttyfd >= 0) {
+			tcsetpgrp(ttyfd, initialpgrp);
+			close(ttyfd);
+			ttyfd = -1;
+		}
+		setsignal(SIGTSTP);
+		setsignal(SIGTTOU);
+		setsignal(SIGTTIN);
+	}
+	jobctl = on;
+}
+#endif
+
+
+#if JOBS
+int
+fgcmd(int argc __unused, char **argv __unused)
+{
+	struct job *jp;
+	pid_t pgrp;
+	int status;
+
+	nextopt("");
+	jp = getjob(*argptr);
+	if (jp->jobctl == 0)
+		error("job not created under job control");
+	printjobcmd(jp);
+	flushout(&output);
+	pgrp = jp->ps[0].pid;
+	if (ttyfd >= 0)
+		tcsetpgrp(ttyfd, pgrp);
+	restartjob(jp);
+	jp->foreground = 1;
+	INTOFF;
+	status = waitforjob(jp, (int *)NULL);
+	INTON;
+	return status;
+}
+
+
+int
+bgcmd(int argc __unused, char **argv __unused)
+{
+	struct job *jp;
+
+	nextopt("");
+	do {
+		jp = getjob(*argptr);
+		if (jp->jobctl == 0)
+			error("job not created under job control");
+		if (jp->state == JOBDONE)
+			continue;
+		restartjob(jp);
+		jp->foreground = 0;
+		out1fmt("[%td] ", jp - jobtab + 1);
+		printjobcmd(jp);
+	} while (*argptr != NULL && *++argptr != NULL);
+	return 0;
+}
+
+
+static void
+restartjob(struct job *jp)
+{
+	struct procstat *ps;
+	int i;
+
+	if (jp->state == JOBDONE)
+		return;
+	setcurjob(jp);
+	INTOFF;
+	kill(-jp->ps[0].pid, SIGCONT);
+	for (ps = jp->ps, i = jp->nprocs ; --i >= 0 ; ps++) {
+		if (WIFSTOPPED(ps->status)) {
+			ps->status = -1;
+			jp->state = 0;
+		}
+	}
+	INTON;
+}
+#endif
+
+
+int
+jobscmd(int argc __unused, char *argv[] __unused)
+{
+	char *id;
+	int ch, mode;
+
+	mode = SHOWJOBS_DEFAULT;
+	while ((ch = nextopt("lps")) != '\0') {
+		switch (ch) {
+		case 'l':
+			mode = SHOWJOBS_VERBOSE;
+			break;
+		case 'p':
+			mode = SHOWJOBS_PGIDS;
+			break;
+		case 's':
+			mode = SHOWJOBS_PIDS;
+			break;
+		}
+	}
+
+	if (*argptr == NULL)
+		showjobs(0, mode);
+	else
+		while ((id = *argptr++) != NULL)
+			showjob(getjob(id), mode);
+
+	return (0);
+}
+
+static void
+printjobcmd(struct job *jp)
+{
+	struct procstat *ps;
+	int i;
+
+	for (ps = jp->ps, i = jp->nprocs ; --i >= 0 ; ps++) {
+		out1str(ps->cmd);
+		if (i > 0)
+			out1str(" | ");
+	}
+	out1c('\n');
+}
+
+static void
+showjob(struct job *jp, int mode)
+{
+	char s[64];
+	char statestr[64];
+	const char *sigstr;
+	struct procstat *ps;
+	struct job *j;
+	int col, curr, i, jobno, prev, procno;
+	char c;
+
+	procno = (mode == SHOWJOBS_PGIDS) ? 1 : jp->nprocs;
+	jobno = jp - jobtab + 1;
+	curr = prev = 0;
+#if JOBS
+	if ((j = getcurjob(NULL)) != NULL) {
+		curr = j - jobtab + 1;
+		if ((j = getcurjob(j)) != NULL)
+			prev = j - jobtab + 1;
+	}
+#endif
+	ps = jp->ps + jp->nprocs - 1;
+	if (jp->state == 0) {
+		strcpy(statestr, "Running");
+#if JOBS
+	} else if (jp->state == JOBSTOPPED) {
+		while (!WIFSTOPPED(ps->status) && ps > jp->ps)
+			ps--;
+		if (WIFSTOPPED(ps->status))
+			i = WSTOPSIG(ps->status);
+		else
+			i = -1;
+		sigstr = strsignal(i);
+		if (sigstr != NULL)
+			strcpy(statestr, sigstr);
+		else
+			strcpy(statestr, "Suspended");
+#endif
+	} else if (WIFEXITED(ps->status)) {
+		if (WEXITSTATUS(ps->status) == 0)
+			strcpy(statestr, "Done");
+		else
+			fmtstr(statestr, 64, "Done(%d)",
+			    WEXITSTATUS(ps->status));
+	} else {
+		i = WTERMSIG(ps->status);
+		sigstr = strsignal(i);
+		if (sigstr != NULL)
+			strcpy(statestr, sigstr);
+		else
+			strcpy(statestr, "Unknown signal");
+		if (WCOREDUMP(ps->status))
+			strcat(statestr, " (core dumped)");
+	}
+
+	for (ps = jp->ps ; procno > 0 ; ps++, procno--) { /* for each process */
+		if (mode == SHOWJOBS_PIDS || mode == SHOWJOBS_PGIDS) {
+			out1fmt("%d\n", (int)ps->pid);
+			continue;
+		}
+		if (mode != SHOWJOBS_VERBOSE && ps != jp->ps)
+			continue;
+		if (jobno == curr && ps == jp->ps)
+			c = '+';
+		else if (jobno == prev && ps == jp->ps)
+			c = '-';
+		else
+			c = ' ';
+		if (ps == jp->ps)
+			fmtstr(s, 64, "[%d] %c ", jobno, c);
+		else
+			fmtstr(s, 64, "    %c ", c);
+		out1str(s);
+		col = strlen(s);
+		if (mode == SHOWJOBS_VERBOSE) {
+			fmtstr(s, 64, "%d ", (int)ps->pid);
+			out1str(s);
+			col += strlen(s);
+		}
+		if (ps == jp->ps) {
+			out1str(statestr);
+			col += strlen(statestr);
+		}
+		do {
+			out1c(' ');
+			col++;
+		} while (col < 30);
+		if (mode == SHOWJOBS_VERBOSE) {
+			out1str(ps->cmd);
+			out1c('\n');
+		} else
+			printjobcmd(jp);
+	}
+}
+
+/*
+ * Print a list of jobs.  If "change" is nonzero, only print jobs whose
+ * statuses have changed since the last call to showjobs.
+ *
+ * If the shell is interrupted in the process of creating a job, the
+ * result may be a job structure containing zero processes.  Such structures
+ * will be freed here.
+ */
+
+void
+showjobs(int change, int mode)
+{
+	int jobno;
+	struct job *jp;
+
+	TRACE(("showjobs(%d) called\n", change));
+	checkzombies();
+	for (jobno = 1, jp = jobtab ; jobno <= njobs ; jobno++, jp++) {
+		if (! jp->used)
+			continue;
+		if (jp->nprocs == 0) {
+			freejob(jp);
+			continue;
+		}
+		if (change && ! jp->changed)
+			continue;
+		showjob(jp, mode);
+		if (mode == SHOWJOBS_DEFAULT || mode == SHOWJOBS_VERBOSE) {
+			jp->changed = 0;
+			/* Hack: discard jobs for which $! has not been
+			 * referenced in interactive mode when they terminate.
+			 */
+			if (jp->state == JOBDONE && !jp->remembered &&
+					(iflag || jp != bgjob)) {
+				freejob(jp);
+			}
+		}
+	}
+}
+
+
+/*
+ * Mark a job structure as unused.
+ */
+
+static void
+freejob(struct job *jp)
+{
+	struct procstat *ps;
+	int i;
+
+	INTOFF;
+	if (bgjob == jp)
+		bgjob = NULL;
+	for (i = jp->nprocs, ps = jp->ps ; --i >= 0 ; ps++) {
+		if (ps->cmd != nullstr)
+			ckfree(ps->cmd);
+	}
+	if (jp->ps != &jp->ps0)
+		ckfree(jp->ps);
+	jp->used = 0;
+#if JOBS
+	deljob(jp);
+#endif
+	INTON;
+}
+
+
+
+int
+waitcmd(int argc __unused, char **argv __unused)
+{
+	struct job *job;
+	int retval;
+
+	nextopt("");
+	if (*argptr == NULL)
+		return (waitcmdloop(NULL));
+
+	do {
+		job = getjob_nonotfound(*argptr);
+		if (job == NULL)
+			retval = 127;
+		else
+			retval = waitcmdloop(job);
+		argptr++;
+	} while (*argptr != NULL);
+
+	return (retval);
+}
+
+static int
+waitcmdloop(struct job *job)
+{
+	int status, retval, sig;
+	struct job *jp;
+
+	/*
+	 * Loop until a process is terminated or stopped, or a SIGINT is
+	 * received.
+	 */
+
+	do {
+		if (job != NULL) {
+			if (job->state == JOBDONE) {
+				status = job->ps[job->nprocs - 1].status;
+				if (WIFEXITED(status))
+					retval = WEXITSTATUS(status);
+				else
+					retval = WTERMSIG(status) + 128;
+				if (! iflag || ! job->changed)
+					freejob(job);
+				else {
+					job->remembered = 0;
+					if (job == bgjob)
+						bgjob = NULL;
+				}
+				return retval;
+			}
+		} else {
+			for (jp = jobtab ; jp < jobtab + njobs; jp++)
+				if (jp->used && jp->state == JOBDONE) {
+					if (! iflag || ! jp->changed)
+						freejob(jp);
+					else {
+						jp->remembered = 0;
+						if (jp == bgjob)
+							bgjob = NULL;
+					}
+				}
+			for (jp = jobtab ; ; jp++) {
+				if (jp >= jobtab + njobs) {	/* no running procs */
+					return 0;
+				}
+				if (jp->used && jp->state == 0)
+					break;
+			}
+		}
+	} while (dowait(DOWAIT_BLOCK | DOWAIT_SIG, (struct job *)NULL) != -1);
+
+	sig = pendingsig_waitcmd;
+	pendingsig_waitcmd = 0;
+	return sig + 128;
+}
+
+
+
+int
+jobidcmd(int argc __unused, char **argv __unused)
+{
+	struct job *jp;
+	int i;
+
+	nextopt("");
+	jp = getjob(*argptr);
+	for (i = 0 ; i < jp->nprocs ; ) {
+		out1fmt("%d", (int)jp->ps[i].pid);
+		out1c(++i < jp->nprocs? ' ' : '\n');
+	}
+	return 0;
+}
+
+
+
+/*
+ * Convert a job name to a job structure.
+ */
+
+static struct job *
+getjob_nonotfound(const char *name)
+{
+	int jobno;
+	struct job *found, *jp;
+	size_t namelen;
+	pid_t pid;
+	int i;
+
+	if (name == NULL) {
+#if JOBS
+		name = "%+";
+#else
+		error("No current job");
+#endif
+	}
+	if (name[0] == '%') {
+		if (is_digit(name[1])) {
+			jobno = number(name + 1);
+			if (jobno > 0 && jobno <= njobs
+			 && jobtab[jobno - 1].used != 0)
+				return &jobtab[jobno - 1];
+#if JOBS
+		} else if ((name[1] == '%' || name[1] == '+') &&
+		    name[2] == '\0') {
+			if ((jp = getcurjob(NULL)) == NULL)
+				error("No current job");
+			return (jp);
+		} else if (name[1] == '-' && name[2] == '\0') {
+			if ((jp = getcurjob(NULL)) == NULL ||
+			    (jp = getcurjob(jp)) == NULL)
+				error("No previous job");
+			return (jp);
+#endif
+		} else if (name[1] == '?') {
+			found = NULL;
+			for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
+				if (jp->used && jp->nprocs > 0
+				 && strstr(jp->ps[0].cmd, name + 2) != NULL) {
+					if (found)
+						error("%s: ambiguous", name);
+					found = jp;
+				}
+			}
+			if (found != NULL)
+				return (found);
+		} else {
+			namelen = strlen(name);
+			found = NULL;
+			for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
+				if (jp->used && jp->nprocs > 0
+				 && strncmp(jp->ps[0].cmd, name + 1,
+				 namelen - 1) == 0) {
+					if (found)
+						error("%s: ambiguous", name);
+					found = jp;
+				}
+			}
+			if (found)
+				return found;
+		}
+	} else if (is_number(name)) {
+		pid = (pid_t)number(name);
+		for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
+			if (jp->used && jp->nprocs > 0
+			 && jp->ps[jp->nprocs - 1].pid == pid)
+				return jp;
+		}
+	}
+	return NULL;
+}
+
+
+static struct job *
+getjob(const char *name)
+{
+	struct job *jp;
+
+	jp = getjob_nonotfound(name);
+	if (jp == NULL)
+		error("No such job: %s", name);
+	return (jp);
+}
+
+
+int
+killjob(const char *name, int sig)
+{
+	struct job *jp;
+	int i, ret;
+
+	jp = getjob(name);
+	if (jp->state == JOBDONE)
+		return 0;
+	if (jp->jobctl)
+		return kill(-jp->ps[0].pid, sig);
+	ret = -1;
+	errno = ESRCH;
+	for (i = 0; i < jp->nprocs; i++)
+		if (jp->ps[i].status == -1 || WIFSTOPPED(jp->ps[i].status)) {
+			if (kill(jp->ps[i].pid, sig) == 0)
+				ret = 0;
+		} else
+			ret = 0;
+	return ret;
+}
+
+/*
+ * Return a new job structure,
+ */
+
+struct job *
+makejob(union node *node __unused, int nprocs)
+{
+	int i;
+	struct job *jp;
+
+	for (i = njobs, jp = jobtab ; ; jp++) {
+		if (--i < 0) {
+			INTOFF;
+			if (njobs == 0) {
+				jobtab = ckmalloc(4 * sizeof jobtab[0]);
+#if JOBS
+				jobmru = NULL;
+#endif
+			} else {
+				jp = ckmalloc((njobs + 4) * sizeof jobtab[0]);
+				memcpy(jp, jobtab, njobs * sizeof jp[0]);
+#if JOBS
+				/* Relocate `next' pointers and list head */
+				if (jobmru != NULL)
+					jobmru = &jp[jobmru - jobtab];
+				for (i = 0; i < njobs; i++)
+					if (jp[i].next != NULL)
+						jp[i].next = &jp[jp[i].next -
+						    jobtab];
+#endif
+				if (bgjob != NULL)
+					bgjob = &jp[bgjob - jobtab];
+				/* Relocate `ps' pointers */
+				for (i = 0; i < njobs; i++)
+					if (jp[i].ps == &jobtab[i].ps0)
+						jp[i].ps = &jp[i].ps0;
+				ckfree(jobtab);
+				jobtab = jp;
+			}
+			jp = jobtab + njobs;
+			for (i = 4 ; --i >= 0 ; jobtab[njobs++].used = 0)
+				;
+			INTON;
+			break;
+		}
+		if (jp->used == 0)
+			break;
+	}
+	INTOFF;
+	jp->state = 0;
+	jp->used = 1;
+	jp->changed = 0;
+	jp->nprocs = 0;
+	jp->foreground = 0;
+	jp->remembered = 0;
+#if JOBS
+	jp->jobctl = jobctl;
+	jp->next = NULL;
+#endif
+	if (nprocs > 1) {
+		jp->ps = ckmalloc(nprocs * sizeof (struct procstat));
+	} else {
+		jp->ps = &jp->ps0;
+	}
+	INTON;
+	TRACE(("makejob(%p, %d) returns %%%td\n", (void *)node, nprocs,
+	    jp - jobtab + 1));
+	return jp;
+}
+
+#if JOBS
+static void
+setcurjob(struct job *cj)
+{
+	struct job *jp, *prev;
+
+	for (prev = NULL, jp = jobmru; jp != NULL; prev = jp, jp = jp->next) {
+		if (jp == cj) {
+			if (prev != NULL)
+				prev->next = jp->next;
+			else
+				jobmru = jp->next;
+			jp->next = jobmru;
+			jobmru = cj;
+			return;
+		}
+	}
+	cj->next = jobmru;
+	jobmru = cj;
+}
+
+static void
+deljob(struct job *j)
+{
+	struct job *jp, *prev;
+
+	for (prev = NULL, jp = jobmru; jp != NULL; prev = jp, jp = jp->next) {
+		if (jp == j) {
+			if (prev != NULL)
+				prev->next = jp->next;
+			else
+				jobmru = jp->next;
+			return;
+		}
+	}
+}
+
+/*
+ * Return the most recently used job that isn't `nj', and preferably one
+ * that is stopped.
+ */
+static struct job *
+getcurjob(struct job *nj)
+{
+	struct job *jp;
+
+	/* Try to find a stopped one.. */
+	for (jp = jobmru; jp != NULL; jp = jp->next)
+		if (jp->used && jp != nj && jp->state == JOBSTOPPED)
+			return (jp);
+	/* Otherwise the most recently used job that isn't `nj' */
+	for (jp = jobmru; jp != NULL; jp = jp->next)
+		if (jp->used && jp != nj)
+			return (jp);
+
+	return (NULL);
+}
+
+#endif
+
+/*
+ * Fork of a subshell.  If we are doing job control, give the subshell its
+ * own process group.  Jp is a job structure that the job is to be added to.
+ * N is the command that will be evaluated by the child.  Both jp and n may
+ * be NULL.  The mode parameter can be one of the following:
+ *	FORK_FG - Fork off a foreground process.
+ *	FORK_BG - Fork off a background process.
+ *	FORK_NOJOB - Like FORK_FG, but don't give the process its own
+ *		     process group even if job control is on.
+ *
+ * When job control is turned off, background processes have their standard
+ * input redirected to /dev/null (except for the second and later processes
+ * in a pipeline).
+ */
+
+pid_t
+forkshell(struct job *jp, union node *n, int mode)
+{
+	pid_t pid;
+	pid_t pgrp;
+
+	TRACE(("forkshell(%%%td, %p, %d) called\n", jp - jobtab, (void *)n,
+	    mode));
+	INTOFF;
+	if (mode == FORK_BG && (jp == NULL || jp->nprocs == 0))
+		checkzombies();
+	flushall();
+	pid = fork();
+	if (pid == -1) {
+		TRACE(("Fork failed, errno=%d\n", errno));
+		INTON;
+		error("Cannot fork: %s", strerror(errno));
+	}
+	if (pid == 0) {
+		struct job *p;
+		int wasroot;
+		int i;
+
+		TRACE(("Child shell %d\n", (int)getpid()));
+		wasroot = rootshell;
+		rootshell = 0;
+		handler = &main_handler;
+		closescript();
+		INTON;
+		forcelocal = 0;
+		clear_traps();
+#if JOBS
+		jobctl = 0;		/* do job control only in root shell */
+		if (wasroot && mode != FORK_NOJOB && mflag) {
+			if (jp == NULL || jp->nprocs == 0)
+				pgrp = getpid();
+			else
+				pgrp = jp->ps[0].pid;
+			if (setpgid(0, pgrp) == 0 && mode == FORK_FG &&
+			    ttyfd >= 0) {
+				/*** this causes superfluous TIOCSPGRPS ***/
+				if (tcsetpgrp(ttyfd, pgrp) < 0)
+					error("tcsetpgrp failed, errno=%d", errno);
+			}
+			setsignal(SIGTSTP);
+			setsignal(SIGTTOU);
+		} else if (mode == FORK_BG) {
+			ignoresig(SIGINT);
+			ignoresig(SIGQUIT);
+			if ((jp == NULL || jp->nprocs == 0) &&
+			    ! fd0_redirected_p ()) {
+				close(0);
+				if (open(_PATH_DEVNULL, O_RDONLY) != 0)
+					error("cannot open %s: %s",
+					    _PATH_DEVNULL, strerror(errno));
+			}
+		}
+#else
+		if (mode == FORK_BG) {
+			ignoresig(SIGINT);
+			ignoresig(SIGQUIT);
+			if ((jp == NULL || jp->nprocs == 0) &&
+			    ! fd0_redirected_p ()) {
+				close(0);
+				if (open(_PATH_DEVNULL, O_RDONLY) != 0)
+					error("cannot open %s: %s",
+					    _PATH_DEVNULL, strerror(errno));
+			}
+		}
+#endif
+		INTOFF;
+		for (i = njobs, p = jobtab ; --i >= 0 ; p++)
+			if (p->used)
+				freejob(p);
+		INTON;
+		if (wasroot && iflag) {
+			setsignal(SIGINT);
+			setsignal(SIGQUIT);
+			setsignal(SIGTERM);
+		}
+		return pid;
+	}
+	if (rootshell && mode != FORK_NOJOB && mflag) {
+		if (jp == NULL || jp->nprocs == 0)
+			pgrp = pid;
+		else
+			pgrp = jp->ps[0].pid;
+		setpgid(pid, pgrp);
+	}
+	if (mode == FORK_BG) {
+		if (bgjob != NULL && bgjob->state == JOBDONE &&
+		    !bgjob->remembered && !iflag)
+			freejob(bgjob);
+		backgndpid = pid;		/* set $! */
+		bgjob = jp;
+	}
+	if (jp) {
+		struct procstat *ps = &jp->ps[jp->nprocs++];
+		ps->pid = pid;
+		ps->status = -1;
+		ps->cmd = nullstr;
+		if (iflag && rootshell && n)
+			ps->cmd = commandtext(n);
+		jp->foreground = mode == FORK_FG;
+#if JOBS
+		setcurjob(jp);
+#endif
+	}
+	INTON;
+	TRACE(("In parent shell:  child = %d\n", (int)pid));
+	return pid;
+}
+
+
+pid_t
+vforkexecshell(struct job *jp, char **argv, char **envp, const char *path, int idx, int pip[2])
+{
+	pid_t pid;
+	struct jmploc jmploc;
+	struct jmploc *savehandler;
+
+	TRACE(("vforkexecshell(%%%td, %s, %p) called\n", jp - jobtab, argv[0],
+	    (void *)pip));
+	INTOFF;
+	flushall();
+	savehandler = handler;
+	pid = vfork();
+	if (pid == -1) {
+		TRACE(("Vfork failed, errno=%d\n", errno));
+		INTON;
+		error("Cannot fork: %s", strerror(errno));
+	}
+	if (pid == 0) {
+		TRACE(("Child shell %d\n", (int)getpid()));
+		if (setjmp(jmploc.loc))
+			_exit(exception == EXEXEC ? exerrno : 2);
+		if (pip != NULL) {
+			close(pip[0]);
+			if (pip[1] != 1) {
+				dup2(pip[1], 1);
+				close(pip[1]);
+			}
+		}
+		handler = &jmploc;
+		shellexec(argv, envp, path, idx);
+	}
+	handler = savehandler;
+	if (jp) {
+		struct procstat *ps = &jp->ps[jp->nprocs++];
+		ps->pid = pid;
+		ps->status = -1;
+		ps->cmd = nullstr;
+		jp->foreground = 1;
+#if JOBS
+		setcurjob(jp);
+#endif
+	}
+	INTON;
+	TRACE(("In parent shell:  child = %d\n", (int)pid));
+	return pid;
+}
+
+
+/*
+ * Wait for job to finish.
+ *
+ * Under job control we have the problem that while a child process is
+ * running interrupts generated by the user are sent to the child but not
+ * to the shell.  This means that an infinite loop started by an inter-
+ * active user may be hard to kill.  With job control turned off, an
+ * interactive user may place an interactive program inside a loop.  If
+ * the interactive program catches interrupts, the user doesn't want
+ * these interrupts to also abort the loop.  The approach we take here
+ * is to have the shell ignore interrupt signals while waiting for a
+ * foreground process to terminate, and then send itself an interrupt
+ * signal if the child process was terminated by an interrupt signal.
+ * Unfortunately, some programs want to do a bit of cleanup and then
+ * exit on interrupt; unless these processes terminate themselves by
+ * sending a signal to themselves (instead of calling exit) they will
+ * confuse this approach.
+ */
+
+int
+waitforjob(struct job *jp, int *origstatus)
+{
+#if JOBS
+	int propagate_int = jp->jobctl && jp->foreground;
+#endif
+	int status;
+	int st;
+
+	INTOFF;
+	TRACE(("waitforjob(%%%td) called\n", jp - jobtab + 1));
+	while (jp->state == 0)
+		if (dowait(DOWAIT_BLOCK | (Tflag ? DOWAIT_SIG |
+		    DOWAIT_SIG_TRAP : 0), jp) == -1)
+			dotrap();
+#if JOBS
+	if (jp->jobctl) {
+		if (ttyfd >= 0 && tcsetpgrp(ttyfd, rootpid) < 0)
+			error("tcsetpgrp failed, errno=%d\n", errno);
+	}
+	if (jp->state == JOBSTOPPED)
+		setcurjob(jp);
+#endif
+	status = jp->ps[jp->nprocs - 1].status;
+	if (origstatus != NULL)
+		*origstatus = status;
+	/* convert to 8 bits */
+	if (WIFEXITED(status))
+		st = WEXITSTATUS(status);
+#if JOBS
+	else if (WIFSTOPPED(status))
+		st = WSTOPSIG(status) + 128;
+#endif
+	else
+		st = WTERMSIG(status) + 128;
+	if (! JOBS || jp->state == JOBDONE)
+		freejob(jp);
+	if (int_pending()) {
+		if (!WIFSIGNALED(status) || WTERMSIG(status) != SIGINT)
+			CLEAR_PENDING_INT;
+	}
+#if JOBS
+	else if (rootshell && iflag && propagate_int &&
+			WIFSIGNALED(status) && WTERMSIG(status) == SIGINT)
+		kill(getpid(), SIGINT);
+#endif
+	INTON;
+	return st;
+}
+
+
+static void
+dummy_handler(int sig __unused)
+{
+}
+
+/*
+ * Wait for a process to terminate.
+ */
+
+static pid_t
+dowait(int mode, struct job *job)
+{
+	struct sigaction sa, osa;
+	sigset_t mask, omask;
+	pid_t pid;
+	int status;
+	struct procstat *sp;
+	struct job *jp;
+	struct job *thisjob;
+	const char *sigstr;
+	int done;
+	int stopped;
+	int sig;
+	int coredump;
+	int wflags;
+	int restore_sigchld;
+
+	TRACE(("dowait(%d, %p) called\n", mode, job));
+	restore_sigchld = 0;
+	if ((mode & DOWAIT_SIG) != 0) {
+		sigfillset(&mask);
+		sigprocmask(SIG_BLOCK, &mask, &omask);
+		INTOFF;
+		if (!issigchldtrapped()) {
+			restore_sigchld = 1;
+			sa.sa_handler = dummy_handler;
+			sa.sa_flags = 0;
+			sigemptyset(&sa.sa_mask);
+			sigaction(SIGCHLD, &sa, &osa);
+		}
+	}
+	do {
+#if JOBS
+		if (iflag)
+			wflags = WUNTRACED | WCONTINUED;
+		else
+#endif
+			wflags = 0;
+		if ((mode & (DOWAIT_BLOCK | DOWAIT_SIG)) != DOWAIT_BLOCK)
+			wflags |= WNOHANG;
+		pid = wait3(&status, wflags, (struct rusage *)NULL);
+		TRACE(("wait returns %d, status=%d\n", (int)pid, status));
+		if (pid == 0 && (mode & DOWAIT_SIG) != 0) {
+			pid = -1;
+			if (((mode & DOWAIT_SIG_TRAP) != 0 ?
+			    pendingsig : pendingsig_waitcmd) != 0) {
+				errno = EINTR;
+				break;
+			}
+			sigsuspend(&omask);
+			if (int_pending())
+				break;
+		}
+	} while (pid == -1 && errno == EINTR);
+	if (pid == -1 && errno == ECHILD && job != NULL)
+		job->state = JOBDONE;
+	if ((mode & DOWAIT_SIG) != 0) {
+		if (restore_sigchld)
+			sigaction(SIGCHLD, &osa, NULL);
+		sigprocmask(SIG_SETMASK, &omask, NULL);
+		INTON;
+	}
+	if (pid <= 0)
+		return pid;
+	INTOFF;
+	thisjob = NULL;
+	for (jp = jobtab ; jp < jobtab + njobs ; jp++) {
+		if (jp->used && jp->nprocs > 0) {
+			done = 1;
+			stopped = 1;
+			for (sp = jp->ps ; sp < jp->ps + jp->nprocs ; sp++) {
+				if (sp->pid == -1)
+					continue;
+				if (sp->pid == pid && (sp->status == -1 ||
+				    WIFSTOPPED(sp->status))) {
+					TRACE(("Changing status of proc %d from 0x%x to 0x%x\n",
+						   (int)pid, sp->status,
+						   status));
+					if (WIFCONTINUED(status)) {
+						sp->status = -1;
+						jp->state = 0;
+					} else
+						sp->status = status;
+					thisjob = jp;
+				}
+				if (sp->status == -1)
+					stopped = 0;
+				else if (WIFSTOPPED(sp->status))
+					done = 0;
+			}
+			if (stopped) {		/* stopped or done */
+				int state = done? JOBDONE : JOBSTOPPED;
+				if (jp->state != state) {
+					TRACE(("Job %td: changing state from %d to %d\n", jp - jobtab + 1, jp->state, state));
+					jp->state = state;
+					if (jp != job) {
+						if (done && !jp->remembered &&
+						    !iflag && jp != bgjob)
+							freejob(jp);
+#if JOBS
+						else if (done)
+							deljob(jp);
+#endif
+					}
+				}
+			}
+		}
+	}
+	INTON;
+	if (!thisjob || thisjob->state == 0)
+		;
+	else if ((!rootshell || !iflag || thisjob == job) &&
+	    thisjob->foreground && thisjob->state != JOBSTOPPED) {
+		sig = 0;
+		coredump = 0;
+		for (sp = thisjob->ps; sp < thisjob->ps + thisjob->nprocs; sp++)
+			if (WIFSIGNALED(sp->status)) {
+				sig = WTERMSIG(sp->status);
+				coredump = WCOREDUMP(sp->status);
+			}
+		if (sig > 0 && sig != SIGINT && sig != SIGPIPE) {
+			sigstr = strsignal(sig);
+			if (sigstr != NULL)
+				out2str(sigstr);
+			else
+				out2str("Unknown signal");
+			if (coredump)
+				out2str(" (core dumped)");
+			out2c('\n');
+			flushout(out2);
+		}
+	} else {
+		TRACE(("Not printing status, rootshell=%d, job=%p\n", rootshell, job));
+		thisjob->changed = 1;
+	}
+	return pid;
+}
+
+
+
+/*
+ * return 1 if there are stopped jobs, otherwise 0
+ */
+int job_warning = 0;
+int
+stoppedjobs(void)
+{
+	int jobno;
+	struct job *jp;
+
+	if (job_warning)
+		return (0);
+	for (jobno = 1, jp = jobtab; jobno <= njobs; jobno++, jp++) {
+		if (jp->used == 0)
+			continue;
+		if (jp->state == JOBSTOPPED) {
+			out2fmt_flush("You have stopped jobs.\n");
+			job_warning = 2;
+			return (1);
+		}
+	}
+
+	return (0);
+}
+
+
+static void
+checkzombies(void)
+{
+	while (njobs > 0 && dowait(0, NULL) > 0)
+		;
+}
+
+
+int
+backgndpidset(void)
+{
+	return backgndpid != -1;
+}
+
+
+pid_t
+backgndpidval(void)
+{
+	if (bgjob != NULL && !forcelocal)
+		bgjob->remembered = 1;
+	return backgndpid;
+}
+
+/*
+ * Return a string identifying a command (to be printed by the
+ * jobs command.
+ */
+
+static char *cmdnextc;
+static int cmdnleft;
+#define MAXCMDTEXT	200
+
+char *
+commandtext(union node *n)
+{
+	char *name;
+
+	cmdnextc = name = ckmalloc(MAXCMDTEXT);
+	cmdnleft = MAXCMDTEXT - 4;
+	cmdtxt(n);
+	*cmdnextc = '\0';
+	return name;
+}
+
+
+static void
+cmdtxtdogroup(union node *n)
+{
+	cmdputs("; do ");
+	cmdtxt(n);
+	cmdputs("; done");
+}
+
+
+static void
+cmdtxtredir(union node *n, const char *op, int deffd)
+{
+	char s[2];
+
+	if (n->nfile.fd != deffd) {
+		s[0] = n->nfile.fd + '0';
+		s[1] = '\0';
+		cmdputs(s);
+	}
+	cmdputs(op);
+	if (n->type == NTOFD || n->type == NFROMFD) {
+		if (n->ndup.dupfd >= 0)
+			s[0] = n->ndup.dupfd + '0';
+		else
+			s[0] = '-';
+		s[1] = '\0';
+		cmdputs(s);
+	} else {
+		cmdtxt(n->nfile.fname);
+	}
+}
+
+
+static void
+cmdtxt(union node *n)
+{
+	union node *np;
+	struct nodelist *lp;
+
+	if (n == NULL)
+		return;
+	switch (n->type) {
+	case NSEMI:
+		cmdtxt(n->nbinary.ch1);
+		cmdputs("; ");
+		cmdtxt(n->nbinary.ch2);
+		break;
+	case NAND:
+		cmdtxt(n->nbinary.ch1);
+		cmdputs(" && ");
+		cmdtxt(n->nbinary.ch2);
+		break;
+	case NOR:
+		cmdtxt(n->nbinary.ch1);
+		cmdputs(" || ");
+		cmdtxt(n->nbinary.ch2);
+		break;
+	case NPIPE:
+		for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
+			cmdtxt(lp->n);
+			if (lp->next)
+				cmdputs(" | ");
+		}
+		break;
+	case NSUBSHELL:
+		cmdputs("(");
+		cmdtxt(n->nredir.n);
+		cmdputs(")");
+		break;
+	case NREDIR:
+	case NBACKGND:
+		cmdtxt(n->nredir.n);
+		break;
+	case NIF:
+		cmdputs("if ");
+		cmdtxt(n->nif.test);
+		cmdputs("; then ");
+		cmdtxt(n->nif.ifpart);
+		cmdputs("...");
+		break;
+	case NWHILE:
+		cmdputs("while ");
+		cmdtxt(n->nbinary.ch1);
+		cmdtxtdogroup(n->nbinary.ch2);
+		break;
+	case NUNTIL:
+		cmdputs("until ");
+		cmdtxt(n->nbinary.ch1);
+		cmdtxtdogroup(n->nbinary.ch2);
+		break;
+	case NFOR:
+		cmdputs("for ");
+		cmdputs(n->nfor.var);
+		cmdputs(" in ...");
+		break;
+	case NCASE:
+		cmdputs("case ");
+		cmdputs(n->ncase.expr->narg.text);
+		cmdputs(" in ...");
+		break;
+	case NDEFUN:
+		cmdputs(n->narg.text);
+		cmdputs("() ...");
+		break;
+	case NNOT:
+		cmdputs("! ");
+		cmdtxt(n->nnot.com);
+		break;
+	case NCMD:
+		for (np = n->ncmd.args ; np ; np = np->narg.next) {
+			cmdtxt(np);
+			if (np->narg.next)
+				cmdputs(" ");
+		}
+		for (np = n->ncmd.redirect ; np ; np = np->nfile.next) {
+			cmdputs(" ");
+			cmdtxt(np);
+		}
+		break;
+	case NARG:
+		cmdputs(n->narg.text);
+		break;
+	case NTO:
+		cmdtxtredir(n, ">", 1);
+		break;
+	case NAPPEND:
+		cmdtxtredir(n, ">>", 1);
+		break;
+	case NTOFD:
+		cmdtxtredir(n, ">&", 1);
+		break;
+	case NCLOBBER:
+		cmdtxtredir(n, ">|", 1);
+		break;
+	case NFROM:
+		cmdtxtredir(n, "<", 0);
+		break;
+	case NFROMTO:
+		cmdtxtredir(n, "<>", 0);
+		break;
+	case NFROMFD:
+		cmdtxtredir(n, "<&", 0);
+		break;
+	case NHERE:
+	case NXHERE:
+		cmdputs("<<...");
+		break;
+	default:
+		cmdputs("???");
+		break;
+	}
+}
+
+
+
+static void
+cmdputs(const char *s)
+{
+	const char *p;
+	char *q;
+	char c;
+	int subtype = 0;
+
+	if (cmdnleft <= 0)
+		return;
+	p = s;
+	q = cmdnextc;
+	while ((c = *p++) != '\0') {
+		if (c == CTLESC)
+			*q++ = *p++;
+		else if (c == CTLVAR) {
+			*q++ = '$';
+			if (--cmdnleft > 0)
+				*q++ = '{';
+			subtype = *p++;
+			if ((subtype & VSTYPE) == VSLENGTH && --cmdnleft > 0)
+				*q++ = '#';
+		} else if (c == '=' && subtype != 0) {
+			*q = "}-+?=##%%\0X"[(subtype & VSTYPE) - VSNORMAL];
+			if (*q)
+				q++;
+			else
+				cmdnleft++;
+			if (((subtype & VSTYPE) == VSTRIMLEFTMAX ||
+			    (subtype & VSTYPE) == VSTRIMRIGHTMAX) &&
+			    --cmdnleft > 0)
+				*q = q[-1], q++;
+			subtype = 0;
+		} else if (c == CTLENDVAR) {
+			*q++ = '}';
+		} else if (c == CTLBACKQ || c == CTLBACKQ+CTLQUOTE) {
+			cmdnleft -= 5;
+			if (cmdnleft > 0) {
+				*q++ = '$';
+				*q++ = '(';
+				*q++ = '.';
+				*q++ = '.';
+				*q++ = '.';
+				*q++ = ')';
+			}
+		} else if (c == CTLARI) {
+			cmdnleft -= 2;
+			if (cmdnleft > 0) {
+				*q++ = '$';
+				*q++ = '(';
+				*q++ = '(';
+			}
+			p++;
+		} else if (c == CTLENDARI) {
+			if (--cmdnleft > 0) {
+				*q++ = ')';
+				*q++ = ')';
+			}
+		} else if (c == CTLQUOTEMARK || c == CTLQUOTEEND)
+			cmdnleft++; /* ignore */
+		else
+			*q++ = c;
+		if (--cmdnleft <= 0) {
+			*q++ = '.';
+			*q++ = '.';
+			*q++ = '.';
+			break;
+		}
+	}
+	cmdnextc = q;
+}
diff --git a/external/sh/jobs.h b/external/sh/jobs.h
new file mode 100644
index 00000000..f9978ded
--- /dev/null
+++ b/external/sh/jobs.h
@@ -0,0 +1,100 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)jobs.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: head/bin/sh/jobs.h 255157 2013-09-02 21:57:46Z jilles $
+ */
+
+/* Mode argument to forkshell.  Don't change FORK_FG or FORK_BG. */
+#define FORK_FG 0
+#define FORK_BG 1
+#define FORK_NOJOB 2
+
+#include <signal.h>		/* for sig_atomic_t */
+
+/*
+ * A job structure contains information about a job.  A job is either a
+ * single process or a set of processes contained in a pipeline.  In the
+ * latter case, pidlist will be non-NULL, and will point to a -1 terminated
+ * array of pids.
+ */
+
+struct procstat {
+	pid_t pid;		/* process id */
+	int status;		/* status flags (defined above) */
+	char *cmd;		/* text of command being run */
+};
+
+
+/* states */
+#define JOBSTOPPED 1		/* all procs are stopped */
+#define JOBDONE 2		/* all procs are completed */
+
+
+struct job {
+	struct procstat ps0;	/* status of process */
+	struct procstat *ps;	/* status or processes when more than one */
+	short nprocs;		/* number of processes */
+	pid_t pgrp;		/* process group of this job */
+	char state;		/* true if job is finished */
+	char used;		/* true if this entry is in used */
+	char changed;		/* true if status has changed */
+	char foreground;	/* true if running in the foreground */
+	char remembered;	/* true if $! referenced */
+#if JOBS
+	char jobctl;		/* job running under job control */
+	struct job *next;	/* job used after this one */
+#endif
+};
+
+enum {
+	SHOWJOBS_DEFAULT,	/* job number, status, command */
+	SHOWJOBS_VERBOSE,	/* job number, PID, status, command */
+	SHOWJOBS_PIDS,		/* PID only */
+	SHOWJOBS_PGIDS		/* PID of the group leader only */
+};
+
+extern int job_warning;		/* user was warned about stopped jobs */
+
+void setjobctl(int);
+void showjobs(int, int);
+struct job *makejob(union node *, int);
+pid_t forkshell(struct job *, union node *, int);
+pid_t vforkexecshell(struct job *, char **, char **, const char *, int, int []);
+int waitforjob(struct job *, int *);
+int stoppedjobs(void);
+int backgndpidset(void);
+pid_t backgndpidval(void);
+char *commandtext(union node *);
+
+#if ! JOBS
+#define setjobctl(on)	/* do nothing */
+#endif
diff --git a/external/sh/kill.c b/external/sh/kill.c
new file mode 100644
index 00000000..9f2470f1
--- /dev/null
+++ b/external/sh/kill.c
@@ -0,0 +1,209 @@
+/*-
+ * Copyright (c) 1988, 1993, 1994
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+/*
+ * Important: This file is used both as a standalone program /bin/kill and
+ * as a builtin for /bin/sh (#define SHELL).
+ */
+
+#if 0
+#ifndef lint
+static char const copyright[] =
+"@(#) Copyright (c) 1988, 1993, 1994\n\
+	The Regents of the University of California.  All rights reserved.\n";
+#endif /* not lint */
+
+#ifndef lint
+static char sccsid[] = "@(#)kill.c	8.4 (Berkeley) 4/28/95";
+#endif /* not lint */
+#endif
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: head/bin/kill/kill.c 279503 2015-03-01 21:46:55Z jilles $");
+
+#include <ctype.h>
+#include <err.h>
+#include <errno.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifdef SHELL
+#define main killcmd
+#include "bltin/bltin.h"
+#endif
+
+static void nosig(const char *);
+static void printsignals(FILE *);
+static int signame_to_signum(const char *);
+static void usage(void);
+
+int
+main(int argc, char *argv[])
+{
+	int errors, numsig, pid, ret;
+	char *ep;
+
+	if (argc < 2)
+		usage();
+
+	numsig = SIGTERM;
+
+	argc--, argv++;
+	if (!strcmp(*argv, "-l")) {
+		argc--, argv++;
+		if (argc > 1)
+			usage();
+		if (argc == 1) {
+			if (!isdigit(**argv))
+				usage();
+			numsig = strtol(*argv, &ep, 10);
+			if (!**argv || *ep)
+				errx(2, "illegal signal number: %s", *argv);
+			if (numsig >= 128)
+				numsig -= 128;
+			if (numsig <= 0 || numsig >= sys_nsig)
+				nosig(*argv);
+			printf("%s\n", sys_signame[numsig]);
+			return (0);
+		}
+		printsignals(stdout);
+		return (0);
+	}
+
+	if (!strcmp(*argv, "-s")) {
+		argc--, argv++;
+		if (argc < 1) {
+			warnx("option requires an argument -- s");
+			usage();
+		}
+		if (strcmp(*argv, "0")) {
+			if ((numsig = signame_to_signum(*argv)) < 0)
+				nosig(*argv);
+		} else
+			numsig = 0;
+		argc--, argv++;
+	} else if (**argv == '-' && *(*argv + 1) != '-') {
+		++*argv;
+		if (isalpha(**argv)) {
+			if ((numsig = signame_to_signum(*argv)) < 0)
+				nosig(*argv);
+		} else if (isdigit(**argv)) {
+			numsig = strtol(*argv, &ep, 10);
+			if (!**argv || *ep)
+				errx(2, "illegal signal number: %s", *argv);
+			if (numsig < 0)
+				nosig(*argv);
+		} else
+			nosig(*argv);
+		argc--, argv++;
+	}
+
+	if (argc > 0 && strncmp(*argv, "--", 2) == 0)
+		argc--, argv++;
+
+	if (argc == 0)
+		usage();
+
+	for (errors = 0; argc; argc--, argv++) {
+#ifdef SHELL
+		if (**argv == '%')
+			ret = killjob(*argv, numsig);
+		else
+#endif
+		{
+			pid = strtol(*argv, &ep, 10);
+			if (!**argv || *ep)
+				errx(2, "illegal process id: %s", *argv);
+			ret = kill(pid, numsig);
+		}
+		if (ret == -1) {
+			warn("%s", *argv);
+			errors = 1;
+		}
+	}
+
+	return (errors);
+}
+
+static int
+signame_to_signum(const char *sig)
+{
+	int n;
+
+	if (strncasecmp(sig, "SIG", 3) == 0)
+		sig += 3;
+	for (n = 1; n < sys_nsig; n++) {
+		if (!strcasecmp(sys_signame[n], sig))
+			return (n);
+	}
+	return (-1);
+}
+
+static void
+nosig(const char *name)
+{
+
+	warnx("unknown signal %s; valid signals:", name);
+	printsignals(stderr);
+#ifdef SHELL
+	error(NULL);
+#else
+	exit(2);
+#endif
+}
+
+static void
+printsignals(FILE *fp)
+{
+	int n;
+
+	for (n = 1; n < sys_nsig; n++) {
+		(void)fprintf(fp, "%s", sys_signame[n]);
+		if (n == (sys_nsig / 2) || n == (sys_nsig - 1))
+			(void)fprintf(fp, "\n");
+		else
+			(void)fprintf(fp, " ");
+	}
+}
+
+static void
+usage(void)
+{
+
+	(void)fprintf(stderr, "%s\n%s\n%s\n%s\n",
+		"usage: kill [-s signal_name] pid ...",
+		"       kill -l [exit_status]",
+		"       kill -signal_name pid ...",
+		"       kill -signal_number pid ...");
+#ifdef SHELL
+	error(NULL);
+#else
+	exit(2);
+#endif
+}
diff --git a/external/sh/mail.c b/external/sh/mail.c
new file mode 100644
index 00000000..b6de32b6
--- /dev/null
+++ b/external/sh/mail.c
@@ -0,0 +1,117 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)mail.c	8.2 (Berkeley) 5/4/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: head/bin/sh/mail.c 278820 2015-02-15 21:47:43Z jilles $");
+
+/*
+ * Routines to check for mail.  (Perhaps make part of main.c?)
+ */
+
+#include "shell.h"
+#include "exec.h"	/* defines padvance() */
+#include "mail.h"
+#include "var.h"
+#include "output.h"
+#include "memalloc.h"
+#include "error.h"
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <stdlib.h>
+
+
+#define MAXMBOXES 10
+
+
+static int nmboxes;			/* number of mailboxes */
+static time_t mailtime[MAXMBOXES];	/* times of mailboxes */
+
+
+
+/*
+ * Print appropriate message(s) if mail has arrived.  If the argument is
+ * nozero, then the value of MAIL has changed, so we just update the
+ * values.
+ */
+
+void
+chkmail(int silent)
+{
+	int i;
+	const char *mpath;
+	char *p;
+	char *q;
+	struct stackmark smark;
+	struct stat statb;
+
+	if (silent)
+		nmboxes = 10;
+	if (nmboxes == 0)
+		return;
+	setstackmark(&smark);
+	mpath = mpathset()? mpathval() : mailval();
+	for (i = 0 ; i < nmboxes ; i++) {
+		p = padvance(&mpath, "");
+		if (p == NULL)
+			break;
+		if (*p == '\0')
+			continue;
+		for (q = p ; *q ; q++);
+		if (q[-1] != '/')
+			abort();
+		q[-1] = '\0';			/* delete trailing '/' */
+#ifdef notdef /* this is what the System V shell claims to do (it lies) */
+		if (stat(p, &statb) < 0)
+			statb.st_mtime = 0;
+		if (statb.st_mtime > mailtime[i] && ! silent) {
+			out2str(pathopt? pathopt : "you have mail");
+			out2c('\n');
+		}
+		mailtime[i] = statb.st_mtime;
+#else /* this is what it should do */
+		if (stat(p, &statb) < 0)
+			statb.st_size = 0;
+		if (statb.st_size > mailtime[i] && ! silent) {
+			out2str(pathopt? pathopt : "you have mail");
+			out2c('\n');
+		}
+		mailtime[i] = statb.st_size;
+#endif
+	}
+	nmboxes = i;
+	popstackmark(&smark);
+}
diff --git a/external/sh/mail.h b/external/sh/mail.h
new file mode 100644
index 00000000..fb5f9088
--- /dev/null
+++ b/external/sh/mail.h
@@ -0,0 +1,36 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)mail.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: head/bin/sh/mail.h 127958 2004-04-06 20:06:54Z markm $
+ */
+
+void chkmail(int);
diff --git a/external/sh/main.c b/external/sh/main.c
new file mode 100644
index 00000000..452ed355
--- /dev/null
+++ b/external/sh/main.c
@@ -0,0 +1,349 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+static char const copyright[] =
+"@(#) Copyright (c) 1991, 1993\n\
+	The Regents of the University of California.  All rights reserved.\n";
+#endif /* not lint */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)main.c	8.6 (Berkeley) 5/28/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: head/bin/sh/main.c 265772 2014-05-09 13:27:30Z jilles $");
+
+#include <stdio.h>
+#include <signal.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <locale.h>
+#include <errno.h>
+
+#include "shell.h"
+#include "main.h"
+#include "mail.h"
+#include "options.h"
+#include "output.h"
+#include "parser.h"
+#include "nodes.h"
+#include "expand.h"
+#include "eval.h"
+#include "jobs.h"
+#include "input.h"
+#include "trap.h"
+#include "var.h"
+#include "show.h"
+#include "memalloc.h"
+#include "error.h"
+#include "mystring.h"
+#include "exec.h"
+#include "cd.h"
+#include "redir.h"
+#include "builtins.h"
+
+int rootpid;
+int rootshell;
+struct jmploc main_handler;
+int localeisutf8, initial_localeisutf8;
+
+static void reset(void);
+static void cmdloop(int);
+static void read_profile(const char *);
+static char *find_dot_file(char *);
+
+/*
+ * Main routine.  We initialize things, parse the arguments, execute
+ * profiles if we're a login shell, and then call cmdloop to execute
+ * commands.  The setjmp call sets up the location to jump to when an
+ * exception occurs.  When an exception occurs the variable "state"
+ * is used to figure out how far we had gotten.
+ */
+
+int
+main(int argc, char *argv[])
+{
+	struct stackmark smark, smark2;
+	volatile int state;
+	char *shinit;
+
+	(void) setlocale(LC_ALL, "");
+	initcharset();
+	state = 0;
+	if (setjmp(main_handler.loc)) {
+		switch (exception) {
+		case EXEXEC:
+			exitstatus = exerrno;
+			break;
+
+		case EXERROR:
+			exitstatus = 2;
+			break;
+
+		default:
+			break;
+		}
+
+		if (state == 0 || iflag == 0 || ! rootshell ||
+		    exception == EXEXIT)
+			exitshell(exitstatus);
+		reset();
+		if (exception == EXINT)
+			out2fmt_flush("\n");
+		popstackmark(&smark);
+		FORCEINTON;				/* enable interrupts */
+		if (state == 1)
+			goto state1;
+		else if (state == 2)
+			goto state2;
+		else if (state == 3)
+			goto state3;
+		else
+			goto state4;
+	}
+	handler = &main_handler;
+#ifdef DEBUG
+	opentrace();
+	trputs("Shell args:  ");  trargs(argv);
+#endif
+	rootpid = getpid();
+	rootshell = 1;
+	INTOFF;
+	initvar();
+	setstackmark(&smark);
+	setstackmark(&smark2);
+	procargs(argc, argv);
+	pwd_init(iflag);
+	INTON;
+	if (iflag)
+		chkmail(1);
+	if (argv[0] && argv[0][0] == '-') {
+		state = 1;
+		read_profile("/etc/profile");
+state1:
+		state = 2;
+		if (privileged == 0)
+			read_profile("${HOME-}/.profile");
+		else
+			read_profile("/etc/suid_profile");
+	}
+state2:
+	state = 3;
+	if (!privileged && iflag) {
+		if ((shinit = lookupvar("ENV")) != NULL && *shinit != '\0') {
+			state = 3;
+			read_profile(shinit);
+		}
+	}
+state3:
+	state = 4;
+	popstackmark(&smark2);
+	if (minusc) {
+		evalstring(minusc, sflag ? 0 : EV_EXIT);
+	}
+state4:
+	if (sflag || minusc == NULL) {
+		cmdloop(1);
+	}
+	exitshell(exitstatus);
+	/*NOTREACHED*/
+	return 0;
+}
+
+static void
+reset(void)
+{
+	reseteval();
+	resetinput();
+}
+
+/*
+ * Read and execute commands.  "Top" is nonzero for the top level command
+ * loop; it turns on prompting if the shell is interactive.
+ */
+
+static void
+cmdloop(int top)
+{
+	union node *n;
+	struct stackmark smark;
+	int inter;
+	int numeof = 0;
+
+	TRACE(("cmdloop(%d) called\n", top));
+	setstackmark(&smark);
+	for (;;) {
+		if (pendingsig)
+			dotrap();
+		inter = 0;
+		if (iflag && top) {
+			inter++;
+			showjobs(1, SHOWJOBS_DEFAULT);
+			chkmail(0);
+			flushout(&output);
+		}
+		n = parsecmd(inter);
+		/* showtree(n); DEBUG */
+		if (n == NEOF) {
+			if (!top || numeof >= 50)
+				break;
+			if (!stoppedjobs()) {
+				if (!Iflag)
+					break;
+				out2fmt_flush("\nUse \"exit\" to leave shell.\n");
+			}
+			numeof++;
+		} else if (n != NULL && nflag == 0) {
+			job_warning = (job_warning == 2) ? 1 : 0;
+			numeof = 0;
+			evaltree(n, 0);
+		}
+		popstackmark(&smark);
+		setstackmark(&smark);
+		if (evalskip != 0) {
+			if (evalskip == SKIPRETURN)
+				evalskip = 0;
+			break;
+		}
+	}
+	popstackmark(&smark);
+}
+
+
+
+/*
+ * Read /etc/profile or .profile.  Return on error.
+ */
+
+static void
+read_profile(const char *name)
+{
+	int fd;
+	const char *expandedname;
+
+	expandedname = expandstr(name);
+	if (expandedname == NULL)
+		return;
+	INTOFF;
+	if ((fd = open(expandedname, O_RDONLY | O_CLOEXEC)) >= 0)
+		setinputfd(fd, 1);
+	INTON;
+	if (fd < 0)
+		return;
+	cmdloop(0);
+	popfile();
+}
+
+
+
+/*
+ * Read a file containing shell functions.
+ */
+
+void
+readcmdfile(const char *name)
+{
+	setinputfile(name, 1);
+	cmdloop(0);
+	popfile();
+}
+
+
+
+/*
+ * Take commands from a file.  To be compatible we should do a path
+ * search for the file, which is necessary to find sub-commands.
+ */
+
+
+static char *
+find_dot_file(char *basename)
+{
+	char *fullname;
+	const char *path = pathval();
+	struct stat statb;
+
+	/* don't try this for absolute or relative paths */
+	if( strchr(basename, '/'))
+		return basename;
+
+	while ((fullname = padvance(&path, basename)) != NULL) {
+		if ((stat(fullname, &statb) == 0) && S_ISREG(statb.st_mode)) {
+			/*
+			 * Don't bother freeing here, since it will
+			 * be freed by the caller.
+			 */
+			return fullname;
+		}
+		stunalloc(fullname);
+	}
+	return basename;
+}
+
+int
+dotcmd(int argc, char **argv)
+{
+	char *filename, *fullname;
+
+	if (argc < 2)
+		error("missing filename");
+
+	exitstatus = 0;
+
+	/*
+	 * Because we have historically not supported any options,
+	 * only treat "--" specially.
+	 */
+	filename = argc > 2 && strcmp(argv[1], "--") == 0 ? argv[2] : argv[1];
+
+	fullname = find_dot_file(filename);
+	setinputfile(fullname, 1);
+	commandname = fullname;
+	cmdloop(0);
+	popfile();
+	return exitstatus;
+}
+
+
+int
+exitcmd(int argc, char **argv)
+{
+	if (stoppedjobs())
+		return 0;
+	if (argc > 1)
+		exitshell(number(argv[1]));
+	else
+		exitshell_savedstatus();
+}
diff --git a/external/sh/main.h b/external/sh/main.h
new file mode 100644
index 00000000..1e1b4996
--- /dev/null
+++ b/external/sh/main.h
@@ -0,0 +1,40 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)main.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: head/bin/sh/main.h 229220 2012-01-01 22:17:12Z jilles $
+ */
+
+extern int rootpid;	/* pid of main shell */
+extern int rootshell;	/* true if we aren't a child of the main shell */
+extern struct jmploc main_handler;	/* top level exception handler */
+
+void readcmdfile(const char *);
diff --git a/external/sh/memalloc.c b/external/sh/memalloc.c
new file mode 100644
index 00000000..32e3838e
--- /dev/null
+++ b/external/sh/memalloc.c
@@ -0,0 +1,342 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)memalloc.c	8.3 (Berkeley) 5/4/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: head/bin/sh/memalloc.c 278818 2015-02-15 21:41:29Z jilles $");
+
+#include <sys/param.h>
+#include "shell.h"
+#include "output.h"
+#include "memalloc.h"
+#include "error.h"
+#include "mystring.h"
+#include "expand.h"
+#include <stdlib.h>
+#include <unistd.h>
+
+/*
+ * Like malloc, but returns an error when out of space.
+ */
+
+pointer
+ckmalloc(size_t nbytes)
+{
+	pointer p;
+
+	INTOFF;
+	p = malloc(nbytes);
+	INTON;
+	if (p == NULL)
+		error("Out of space");
+	return p;
+}
+
+
+/*
+ * Same for realloc.
+ */
+
+pointer
+ckrealloc(pointer p, int nbytes)
+{
+	INTOFF;
+	p = realloc(p, nbytes);
+	INTON;
+	if (p == NULL)
+		error("Out of space");
+	return p;
+}
+
+void
+ckfree(pointer p)
+{
+	INTOFF;
+	free(p);
+	INTON;
+}
+
+
+/*
+ * Make a copy of a string in safe storage.
+ */
+
+char *
+savestr(const char *s)
+{
+	char *p;
+	size_t len;
+
+	len = strlen(s);
+	p = ckmalloc(len + 1);
+	memcpy(p, s, len + 1);
+	return p;
+}
+
+
+/*
+ * Parse trees for commands are allocated in lifo order, so we use a stack
+ * to make this more efficient, and also to avoid all sorts of exception
+ * handling code to handle interrupts in the middle of a parse.
+ *
+ * The size 496 was chosen because with 16-byte alignment the total size
+ * for the allocated block is 512.
+ */
+
+#define MINSIZE 496		/* minimum size of a block. */
+
+
+struct stack_block {
+	struct stack_block *prev;
+	/* Data follows */
+};
+#define SPACE(sp)	((char*)(sp) + ALIGN(sizeof(struct stack_block)))
+
+static struct stack_block *stackp;
+char *stacknxt;
+int stacknleft;
+char *sstrend;
+
+
+static void
+stnewblock(int nbytes)
+{
+	struct stack_block *sp;
+	int allocsize;
+
+	if (nbytes < MINSIZE)
+		nbytes = MINSIZE;
+
+	allocsize = ALIGN(sizeof(struct stack_block)) + ALIGN(nbytes);
+
+	INTOFF;
+	sp = ckmalloc(allocsize);
+	sp->prev = stackp;
+	stacknxt = SPACE(sp);
+	stacknleft = allocsize - (stacknxt - (char*)sp);
+	sstrend = stacknxt + stacknleft;
+	stackp = sp;
+	INTON;
+}
+
+
+pointer
+stalloc(int nbytes)
+{
+	char *p;
+
+	nbytes = ALIGN(nbytes);
+	if (nbytes > stacknleft)
+		stnewblock(nbytes);
+	p = stacknxt;
+	stacknxt += nbytes;
+	stacknleft -= nbytes;
+	return p;
+}
+
+
+void
+stunalloc(pointer p)
+{
+	if (p == NULL) {		/*DEBUG */
+		write(STDERR_FILENO, "stunalloc\n", 10);
+		abort();
+	}
+	stacknleft += stacknxt - (char *)p;
+	stacknxt = p;
+}
+
+
+char *
+stsavestr(const char *s)
+{
+	char *p;
+	size_t len;
+
+	len = strlen(s);
+	p = stalloc(len + 1);
+	memcpy(p, s, len + 1);
+	return p;
+}
+
+
+void
+setstackmark(struct stackmark *mark)
+{
+	mark->stackp = stackp;
+	mark->stacknxt = stacknxt;
+	mark->stacknleft = stacknleft;
+	/* Ensure this block stays in place. */
+	if (stackp != NULL && stacknxt == SPACE(stackp))
+		stalloc(1);
+}
+
+
+void
+popstackmark(struct stackmark *mark)
+{
+	struct stack_block *sp;
+
+	INTOFF;
+	while (stackp != mark->stackp) {
+		sp = stackp;
+		stackp = sp->prev;
+		ckfree(sp);
+	}
+	stacknxt = mark->stacknxt;
+	stacknleft = mark->stacknleft;
+	sstrend = stacknxt + stacknleft;
+	INTON;
+}
+
+
+/*
+ * When the parser reads in a string, it wants to stick the string on the
+ * stack and only adjust the stack pointer when it knows how big the
+ * string is.  Stackblock (defined in stack.h) returns a pointer to a block
+ * of space on top of the stack and stackblocklen returns the length of
+ * this block.  Growstackblock will grow this space by at least one byte,
+ * possibly moving it (like realloc).  Grabstackblock actually allocates the
+ * part of the block that has been used.
+ */
+
+static void
+growstackblock(int min)
+{
+	char *p;
+	int newlen;
+	char *oldspace;
+	int oldlen;
+	struct stack_block *sp;
+	struct stack_block *oldstackp;
+
+	if (min < stacknleft)
+		min = stacknleft;
+	if ((unsigned int)min >=
+	    INT_MAX / 2 - ALIGN(sizeof(struct stack_block)))
+		error("Out of space");
+	min += stacknleft;
+	min += ALIGN(sizeof(struct stack_block));
+	newlen = 512;
+	while (newlen < min)
+		newlen <<= 1;
+	oldspace = stacknxt;
+	oldlen = stacknleft;
+
+	if (stackp != NULL && stacknxt == SPACE(stackp)) {
+		INTOFF;
+		oldstackp = stackp;
+		stackp = oldstackp->prev;
+		sp = ckrealloc((pointer)oldstackp, newlen);
+		sp->prev = stackp;
+		stackp = sp;
+		stacknxt = SPACE(sp);
+		stacknleft = newlen - (stacknxt - (char*)sp);
+		sstrend = stacknxt + stacknleft;
+		INTON;
+	} else {
+		newlen -= ALIGN(sizeof(struct stack_block));
+		p = stalloc(newlen);
+		if (oldlen != 0)
+			memcpy(p, oldspace, oldlen);
+		stunalloc(p);
+	}
+}
+
+
+
+/*
+ * The following routines are somewhat easier to use that the above.
+ * The user declares a variable of type STACKSTR, which may be declared
+ * to be a register.  The macro STARTSTACKSTR initializes things.  Then
+ * the user uses the macro STPUTC to add characters to the string.  In
+ * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is
+ * grown as necessary.  When the user is done, she can just leave the
+ * string there and refer to it using stackblock().  Or she can allocate
+ * the space for it using grabstackstr().  If it is necessary to allow
+ * someone else to use the stack temporarily and then continue to grow
+ * the string, the user should use grabstack to allocate the space, and
+ * then call ungrabstr(p) to return to the previous mode of operation.
+ *
+ * USTPUTC is like STPUTC except that it doesn't check for overflow.
+ * CHECKSTACKSPACE can be called before USTPUTC to ensure that there
+ * is space for at least one character.
+ */
+
+static char *
+growstrstackblock(int n, int min)
+{
+	growstackblock(min);
+	return stackblock() + n;
+}
+
+char *
+growstackstr(void)
+{
+	int len;
+
+	len = stackblocksize();
+	return (growstrstackblock(len, 0));
+}
+
+
+/*
+ * Called from CHECKSTRSPACE.
+ */
+
+char *
+makestrspace(int min, char *p)
+{
+	int len;
+
+	len = p - stackblock();
+	return (growstrstackblock(len, min));
+}
+
+
+char *
+stputbin(const char *data, size_t len, char *p)
+{
+	CHECKSTRSPACE(len, p);
+	memcpy(p, data, len);
+	return (p + len);
+}
+
+char *
+stputs(const char *data, char *p)
+{
+	return (stputbin(data, strlen(data), p));
+}
diff --git a/external/sh/memalloc.h b/external/sh/memalloc.h
new file mode 100644
index 00000000..ee86a922
--- /dev/null
+++ b/external/sh/memalloc.h
@@ -0,0 +1,86 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)memalloc.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: head/bin/sh/memalloc.h 278818 2015-02-15 21:41:29Z jilles $
+ */
+
+#include <string.h>
+
+struct stackmark {
+	struct stack_block *stackp;
+	char *stacknxt;
+	int stacknleft;
+};
+
+
+extern char *stacknxt;
+extern int stacknleft;
+extern char *sstrend;
+
+pointer ckmalloc(size_t);
+pointer ckrealloc(pointer, int);
+void ckfree(pointer);
+char *savestr(const char *);
+pointer stalloc(int);
+void stunalloc(pointer);
+char *stsavestr(const char *);
+void setstackmark(struct stackmark *);
+void popstackmark(struct stackmark *);
+char *growstackstr(void);
+char *makestrspace(int, char *);
+char *stputbin(const char *data, size_t len, char *p);
+char *stputs(const char *data, char *p);
+
+
+
+#define stackblock() stacknxt
+#define stackblocksize() stacknleft
+#define grabstackblock(n) stalloc(n)
+#define STARTSTACKSTR(p)	p = stackblock()
+#define STPUTC(c, p)	do { if (p == sstrend) p = growstackstr(); *p++ = (c); } while(0)
+#define CHECKSTRSPACE(n, p)	{ if ((size_t)(sstrend - p) < n) p = makestrspace(n, p); }
+#define USTPUTC(c, p)	(*p++ = (c))
+/*
+ * STACKSTRNUL's use is where we want to be able to turn a stack
+ * (non-sentinel, character counting string) into a C string,
+ * and later pretend the NUL is not there.
+ * Note: Because of STACKSTRNUL's semantics, STACKSTRNUL cannot be used
+ * on a stack that will grabstackstr()ed.
+ */
+#define STACKSTRNUL(p)	(p == sstrend ? (p = growstackstr(), *p = '\0') : (*p = '\0'))
+#define STUNPUTC(p)	(--p)
+#define STTOPC(p)	p[-1]
+#define STADJUST(amount, p)	(p += (amount))
+#define grabstackstr(p)	stalloc((char *)p - stackblock())
+#define ungrabstackstr(s, p)	stunalloc((s))
+#define STPUTBIN(s, len, p)	p = stputbin((s), (len), p)
+#define STPUTS(s, p)	p = stputs((s), p)
diff --git a/external/sh/miscbltin.c b/external/sh/miscbltin.c
new file mode 100644
index 00000000..08121349
--- /dev/null
+++ b/external/sh/miscbltin.c
@@ -0,0 +1,523 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)miscbltin.c	8.4 (Berkeley) 5/4/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: head/bin/sh/miscbltin.c 278820 2015-02-15 21:47:43Z jilles $");
+
+/*
+ * Miscellaneous builtins.
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+#include <unistd.h>
+#include <errno.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "shell.h"
+#include "options.h"
+#include "var.h"
+#include "output.h"
+#include "memalloc.h"
+#include "error.h"
+#include "mystring.h"
+#include "syntax.h"
+#include "trap.h"
+
+#undef eflag
+
+int readcmd(int, char **);
+int umaskcmd(int, char **);
+int ulimitcmd(int, char **);
+
+/*
+ * The read builtin.  The -r option causes backslashes to be treated like
+ * ordinary characters.
+ *
+ * This uses unbuffered input, which may be avoidable in some cases.
+ *
+ * Note that if IFS=' :' then read x y should work so that:
+ * 'a b'	x='a', y='b'
+ * ' a b '	x='a', y='b'
+ * ':b'		x='',  y='b'
+ * ':'		x='',  y=''
+ * '::'		x='',  y=''
+ * ': :'	x='',  y=''
+ * ':::'	x='',  y='::'
+ * ':b c:'	x='',  y='b c:'
+ */
+
+int
+readcmd(int argc __unused, char **argv __unused)
+{
+	char **ap;
+	int backslash;
+	char c;
+	int rflag;
+	char *prompt;
+	const char *ifs;
+	char *p;
+	int startword;
+	int status;
+	int i;
+	int is_ifs;
+	int saveall = 0;
+	struct timeval tv;
+	char *tvptr;
+	fd_set ifds;
+	ssize_t nread;
+	int sig;
+
+	rflag = 0;
+	prompt = NULL;
+	tv.tv_sec = -1;
+	tv.tv_usec = 0;
+	while ((i = nextopt("erp:t:")) != '\0') {
+		switch(i) {
+		case 'p':
+			prompt = shoptarg;
+			break;
+		case 'e':
+			break;
+		case 'r':
+			rflag = 1;
+			break;
+		case 't':
+			tv.tv_sec = strtol(shoptarg, &tvptr, 0);
+			if (tvptr == shoptarg)
+				error("timeout value");
+			switch(*tvptr) {
+			case 0:
+			case 's':
+				break;
+			case 'h':
+				tv.tv_sec *= 60;
+				/* FALLTHROUGH */
+			case 'm':
+				tv.tv_sec *= 60;
+				break;
+			default:
+				error("timeout unit");
+			}
+			break;
+		}
+	}
+	if (prompt && isatty(0)) {
+		out2str(prompt);
+		flushall();
+	}
+	if (*(ap = argptr) == NULL)
+		error("arg count");
+	if ((ifs = bltinlookup("IFS", 1)) == NULL)
+		ifs = " \t\n";
+
+	if (tv.tv_sec >= 0) {
+		/*
+		 * Wait for something to become available.
+		 */
+		FD_ZERO(&ifds);
+		FD_SET(0, &ifds);
+		status = select(1, &ifds, NULL, NULL, &tv);
+		/*
+		 * If there's nothing ready, return an error.
+		 */
+		if (status <= 0) {
+			sig = pendingsig;
+			return (128 + (sig != 0 ? sig : SIGALRM));
+		}
+	}
+
+	status = 0;
+	startword = 2;
+	backslash = 0;
+	STARTSTACKSTR(p);
+	for (;;) {
+		nread = read(STDIN_FILENO, &c, 1);
+		if (nread == -1) {
+			if (errno == EINTR) {
+				sig = pendingsig;
+				if (sig == 0)
+					continue;
+				status = 128 + sig;
+				break;
+			}
+			warning("read error: %s", strerror(errno));
+			status = 2;
+			break;
+		} else if (nread != 1) {
+			status = 1;
+			break;
+		}
+		if (c == '\0')
+			continue;
+		CHECKSTRSPACE(1, p);
+		if (backslash) {
+			backslash = 0;
+			startword = 0;
+			if (c != '\n')
+				USTPUTC(c, p);
+			continue;
+		}
+		if (!rflag && c == '\\') {
+			backslash++;
+			continue;
+		}
+		if (c == '\n')
+			break;
+		if (strchr(ifs, c))
+			is_ifs = strchr(" \t\n", c) ? 1 : 2;
+		else
+			is_ifs = 0;
+
+		if (startword != 0) {
+			if (is_ifs == 1) {
+				/* Ignore leading IFS whitespace */
+				if (saveall)
+					USTPUTC(c, p);
+				continue;
+			}
+			if (is_ifs == 2 && startword == 1) {
+				/* Only one non-whitespace IFS per word */
+				startword = 2;
+				if (saveall)
+					USTPUTC(c, p);
+				continue;
+			}
+		}
+
+		if (is_ifs == 0) {
+			/* append this character to the current variable */
+			startword = 0;
+			if (saveall)
+				/* Not just a spare terminator */
+				saveall++;
+			USTPUTC(c, p);
+			continue;
+		}
+
+		/* end of variable... */
+		startword = is_ifs;
+
+		if (ap[1] == NULL) {
+			/* Last variable needs all IFS chars */
+			saveall++;
+			USTPUTC(c, p);
+			continue;
+		}
+
+		STACKSTRNUL(p);
+		setvar(*ap, stackblock(), 0);
+		ap++;
+		STARTSTACKSTR(p);
+	}
+	STACKSTRNUL(p);
+
+	/* Remove trailing IFS chars */
+	for (; stackblock() <= --p; *p = 0) {
+		if (!strchr(ifs, *p))
+			break;
+		if (strchr(" \t\n", *p))
+			/* Always remove whitespace */
+			continue;
+		if (saveall > 1)
+			/* Don't remove non-whitespace unless it was naked */
+			break;
+	}
+	setvar(*ap, stackblock(), 0);
+
+	/* Set any remaining args to "" */
+	while (*++ap != NULL)
+		setvar(*ap, "", 0);
+	return status;
+}
+
+
+
+int
+umaskcmd(int argc __unused, char **argv __unused)
+{
+	char *ap;
+	int mask;
+	int i;
+	int symbolic_mode = 0;
+
+	while ((i = nextopt("S")) != '\0') {
+		symbolic_mode = 1;
+	}
+
+	INTOFF;
+	mask = umask(0);
+	umask(mask);
+	INTON;
+
+	if ((ap = *argptr) == NULL) {
+		if (symbolic_mode) {
+			char u[4], g[4], o[4];
+
+			i = 0;
+			if ((mask & S_IRUSR) == 0)
+				u[i++] = 'r';
+			if ((mask & S_IWUSR) == 0)
+				u[i++] = 'w';
+			if ((mask & S_IXUSR) == 0)
+				u[i++] = 'x';
+			u[i] = '\0';
+
+			i = 0;
+			if ((mask & S_IRGRP) == 0)
+				g[i++] = 'r';
+			if ((mask & S_IWGRP) == 0)
+				g[i++] = 'w';
+			if ((mask & S_IXGRP) == 0)
+				g[i++] = 'x';
+			g[i] = '\0';
+
+			i = 0;
+			if ((mask & S_IROTH) == 0)
+				o[i++] = 'r';
+			if ((mask & S_IWOTH) == 0)
+				o[i++] = 'w';
+			if ((mask & S_IXOTH) == 0)
+				o[i++] = 'x';
+			o[i] = '\0';
+
+			out1fmt("u=%s,g=%s,o=%s\n", u, g, o);
+		} else {
+			out1fmt("%.4o\n", mask);
+		}
+	} else {
+		if (is_digit(*ap)) {
+			mask = 0;
+			do {
+				if (*ap >= '8' || *ap < '0')
+					error("Illegal number: %s", *argptr);
+				mask = (mask << 3) + (*ap - '0');
+			} while (*++ap != '\0');
+			umask(mask);
+		} else {
+			void *set;
+			INTOFF;
+			if ((set = setmode (ap)) == 0)
+				error("Illegal number: %s", ap);
+
+			mask = getmode (set, ~mask & 0777);
+			umask(~mask & 0777);
+			free(set);
+			INTON;
+		}
+	}
+	return 0;
+}
+
+/*
+ * ulimit builtin
+ *
+ * This code, originally by Doug Gwyn, Doug Kingston, Eric Gisin, and
+ * Michael Rendell was ripped from pdksh 5.0.8 and hacked for use with
+ * ash by J.T. Conklin.
+ *
+ * Public domain.
+ */
+
+struct limits {
+	const char *name;
+	const char *units;
+	int	cmd;
+	int	factor;	/* multiply by to get rlim_{cur,max} values */
+	char	option;
+};
+
+static const struct limits limits[] = {
+#ifdef RLIMIT_CPU
+	{ "cpu time",		"seconds",	RLIMIT_CPU,	   1, 't' },
+#endif
+#ifdef RLIMIT_FSIZE
+	{ "file size",		"512-blocks",	RLIMIT_FSIZE,	 512, 'f' },
+#endif
+#ifdef RLIMIT_DATA
+	{ "data seg size",	"kbytes",	RLIMIT_DATA,	1024, 'd' },
+#endif
+#ifdef RLIMIT_STACK
+	{ "stack size",		"kbytes",	RLIMIT_STACK,	1024, 's' },
+#endif
+#ifdef  RLIMIT_CORE
+	{ "core file size",	"512-blocks",	RLIMIT_CORE,	 512, 'c' },
+#endif
+#ifdef RLIMIT_RSS
+	{ "max memory size",	"kbytes",	RLIMIT_RSS,	1024, 'm' },
+#endif
+#ifdef RLIMIT_MEMLOCK
+	{ "locked memory",	"kbytes",	RLIMIT_MEMLOCK, 1024, 'l' },
+#endif
+#ifdef RLIMIT_NPROC
+	{ "max user processes",	(char *)0,	RLIMIT_NPROC,      1, 'u' },
+#endif
+#ifdef RLIMIT_NOFILE
+	{ "open files",		(char *)0,	RLIMIT_NOFILE,     1, 'n' },
+#endif
+#ifdef RLIMIT_VMEM
+	{ "virtual mem size",	"kbytes",	RLIMIT_VMEM,	1024, 'v' },
+#endif
+#ifdef RLIMIT_SWAP
+	{ "swap limit",		"kbytes",	RLIMIT_SWAP,	1024, 'w' },
+#endif
+#ifdef RLIMIT_SBSIZE
+	{ "sbsize",		"bytes",	RLIMIT_SBSIZE,	   1, 'b' },
+#endif
+#ifdef RLIMIT_NPTS
+	{ "pseudo-terminals",	(char *)0,	RLIMIT_NPTS,	   1, 'p' },
+#endif
+#ifdef RLIMIT_KQUEUES
+	{ "kqueues",		(char *)0,	RLIMIT_KQUEUES,	   1, 'k' },
+#endif
+	{ (char *) 0,		(char *)0,	0,		   0, '\0' }
+};
+
+enum limithow { SOFT = 0x1, HARD = 0x2 };
+
+static void
+printlimit(enum limithow how, const struct rlimit *limit,
+    const struct limits *l)
+{
+	rlim_t val = 0;
+
+	if (how & SOFT)
+		val = limit->rlim_cur;
+	else if (how & HARD)
+		val = limit->rlim_max;
+	if (val == RLIM_INFINITY)
+		out1str("unlimited\n");
+	else
+	{
+		val /= l->factor;
+		out1fmt("%jd\n", (intmax_t)val);
+	}
+}
+
+int
+ulimitcmd(int argc __unused, char **argv __unused)
+{
+	rlim_t val = 0;
+	enum limithow how = SOFT | HARD;
+	const struct limits	*l;
+	int		set, all = 0;
+	int		optc, what;
+	struct rlimit	limit;
+
+	what = 'f';
+	while ((optc = nextopt("HSatfdsmcnuvlbpwk")) != '\0')
+		switch (optc) {
+		case 'H':
+			how = HARD;
+			break;
+		case 'S':
+			how = SOFT;
+			break;
+		case 'a':
+			all = 1;
+			break;
+		default:
+			what = optc;
+		}
+
+	for (l = limits; l->name && l->option != what; l++)
+		;
+	if (!l->name)
+		error("internal error (%c)", what);
+
+	set = *argptr ? 1 : 0;
+	if (set) {
+		char *p = *argptr;
+
+		if (all || argptr[1])
+			error("too many arguments");
+		if (strcmp(p, "unlimited") == 0)
+			val = RLIM_INFINITY;
+		else {
+			char *end;
+			uintmax_t uval;
+
+			if (*p < '0' || *p > '9')
+				error("bad number");
+			errno = 0;
+			uval = strtoumax(p, &end, 10);
+			if (errno != 0 || *end != '\0')
+				error("bad number");
+			if (uval > UINTMAX_MAX / l->factor)
+				error("bad number");
+			uval *= l->factor;
+			val = (rlim_t)uval;
+			if (val < 0 || (uintmax_t)val != uval ||
+			    val == RLIM_INFINITY)
+				error("bad number");
+		}
+	}
+	if (all) {
+		for (l = limits; l->name; l++) {
+			char optbuf[40];
+			if (getrlimit(l->cmd, &limit) < 0)
+				error("can't get limit: %s", strerror(errno));
+
+			if (l->units)
+				snprintf(optbuf, sizeof(optbuf),
+					"(%s, -%c) ", l->units, l->option);
+			else
+				snprintf(optbuf, sizeof(optbuf),
+					"(-%c) ", l->option);
+			out1fmt("%-18s %18s ", l->name, optbuf);
+			printlimit(how, &limit, l);
+		}
+		return 0;
+	}
+
+	if (getrlimit(l->cmd, &limit) < 0)
+		error("can't get limit: %s", strerror(errno));
+	if (set) {
+		if (how & SOFT)
+			limit.rlim_cur = val;
+		if (how & HARD)
+			limit.rlim_max = val;
+		if (setrlimit(l->cmd, &limit) < 0)
+			error("bad limit: %s", strerror(errno));
+	} else
+		printlimit(how, &limit, l);
+	return 0;
+}
diff --git a/external/sh/myhistedit.h b/external/sh/myhistedit.h
new file mode 100644
index 00000000..1d21f467
--- /dev/null
+++ b/external/sh/myhistedit.h
@@ -0,0 +1,42 @@
+/*-
+ * Copyright (c) 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)myhistedit.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: head/bin/sh/myhistedit.h 229220 2012-01-01 22:17:12Z jilles $
+ */
+
+#include <histedit.h>
+
+extern History *hist;
+extern EditLine *el;
+extern int displayhist;
+
+void histedit(void);
+void sethistsize(const char *);
+void setterm(const char *);
+
diff --git a/external/sh/mystring.c b/external/sh/mystring.c
new file mode 100644
index 00000000..60349d7e
--- /dev/null
+++ b/external/sh/mystring.c
@@ -0,0 +1,98 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)mystring.c	8.2 (Berkeley) 5/4/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: head/bin/sh/mystring.c 270102 2014-08-17 16:40:29Z jilles $");
+
+/*
+ * String functions.
+ *
+ *	equal(s1, s2)		Return true if strings are equal.
+ *	number(s)		Convert a string of digits to an integer.
+ *	is_number(s)		Return true if s is a string of digits.
+ */
+
+#include <stdlib.h>
+#include "shell.h"
+#include "syntax.h"
+#include "error.h"
+#include "mystring.h"
+
+
+char nullstr[1];		/* zero length string */
+
+/*
+ * equal - #defined in mystring.h
+ */
+
+
+/*
+ * Convert a string of digits to an integer, printing an error message on
+ * failure.
+ */
+
+int
+number(const char *s)
+{
+	if (! is_number(s))
+		error("Illegal number: %s", s);
+	return atoi(s);
+}
+
+
+
+/*
+ * Check for a valid number.  This should be elsewhere.
+ */
+
+int
+is_number(const char *p)
+{
+	const char *q;
+
+	if (*p == '\0')
+		return 0;
+	while (*p == '0')
+		p++;
+	for (q = p; *q != '\0'; q++)
+		if (! is_digit(*q))
+			return 0;
+	if (q - p > 10 ||
+	    (q - p == 10 && memcmp(p, "2147483647", 10) > 0))
+		return 0;
+	return 1;
+}
diff --git a/external/sh/mystring.h b/external/sh/mystring.h
new file mode 100644
index 00000000..3876bab5
--- /dev/null
+++ b/external/sh/mystring.h
@@ -0,0 +1,41 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)mystring.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: head/bin/sh/mystring.h 268920 2014-07-20 12:06:52Z jilles $
+ */
+
+#include <string.h>
+
+int number(const char *);
+int is_number(const char *);
+
+#define equal(s1, s2)	(strcmp(s1, s2) == 0)
diff --git a/external/sh/nodes.c b/external/sh/nodes.c
new file mode 100644
index 00000000..956a4ded
--- /dev/null
+++ b/external/sh/nodes.c
@@ -0,0 +1,368 @@
+/*
+ * This file was generated by the mknodes program.
+ */
+
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)nodes.c.pat	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: head/bin/sh/nodes.c.pat 249235 2013-04-07 16:28:36Z jilles $
+ */
+
+#include <sys/param.h>
+#include <stdlib.h>
+#include <stddef.h>
+/*
+ * Routine for dealing with parsed shell commands.
+ */
+
+#include "shell.h"
+#include "nodes.h"
+#include "memalloc.h"
+#include "mystring.h"
+
+
+static int     funcblocksize;	/* size of structures in function */
+static int     funcstringsize;	/* size of strings in node */
+static pointer funcblock;	/* block to allocate function from */
+static char   *funcstring;	/* block to allocate strings from */
+
+static const short nodesize[27] = {
+      ALIGN(sizeof (struct nbinary)),
+      ALIGN(sizeof (struct ncmd)),
+      ALIGN(sizeof (struct npipe)),
+      ALIGN(sizeof (struct nredir)),
+      ALIGN(sizeof (struct nredir)),
+      ALIGN(sizeof (struct nredir)),
+      ALIGN(sizeof (struct nbinary)),
+      ALIGN(sizeof (struct nbinary)),
+      ALIGN(sizeof (struct nif)),
+      ALIGN(sizeof (struct nbinary)),
+      ALIGN(sizeof (struct nbinary)),
+      ALIGN(sizeof (struct nfor)),
+      ALIGN(sizeof (struct ncase)),
+      ALIGN(sizeof (struct nclist)),
+      ALIGN(sizeof (struct nclist)),
+      ALIGN(sizeof (struct narg)),
+      ALIGN(sizeof (struct narg)),
+      ALIGN(sizeof (struct nfile)),
+      ALIGN(sizeof (struct nfile)),
+      ALIGN(sizeof (struct nfile)),
+      ALIGN(sizeof (struct nfile)),
+      ALIGN(sizeof (struct nfile)),
+      ALIGN(sizeof (struct ndup)),
+      ALIGN(sizeof (struct ndup)),
+      ALIGN(sizeof (struct nhere)),
+      ALIGN(sizeof (struct nhere)),
+      ALIGN(sizeof (struct nnot)),
+};
+
+
+static void calcsize(union node *);
+static void sizenodelist(struct nodelist *);
+static union node *copynode(union node *);
+static struct nodelist *copynodelist(struct nodelist *);
+static char *nodesavestr(const char *);
+
+
+struct funcdef {
+	unsigned int refcount;
+	union node n;
+};
+
+/*
+ * Make a copy of a parse tree.
+ */
+
+struct funcdef *
+copyfunc(union node *n)
+{
+	struct funcdef *fn;
+
+	if (n == NULL)
+		return NULL;
+	funcblocksize = offsetof(struct funcdef, n);
+	funcstringsize = 0;
+	calcsize(n);
+	fn = ckmalloc(funcblocksize + funcstringsize);
+	fn->refcount = 1;
+	funcblock = (char *)fn + offsetof(struct funcdef, n);
+	funcstring = (char *)fn + funcblocksize;
+	copynode(n);
+	return fn;
+}
+
+
+union node *
+getfuncnode(struct funcdef *fn)
+{
+	return fn == NULL ? NULL : &fn->n;
+}
+
+
+static void
+calcsize(union node *n)
+{
+      if (n == NULL)
+	    return;
+      funcblocksize += nodesize[n->type];
+      switch (n->type) {
+      case NSEMI:
+      case NAND:
+      case NOR:
+      case NWHILE:
+      case NUNTIL:
+	    calcsize(n->nbinary.ch2);
+	    calcsize(n->nbinary.ch1);
+	    break;
+      case NCMD:
+	    calcsize(n->ncmd.redirect);
+	    calcsize(n->ncmd.args);
+	    break;
+      case NPIPE:
+	    sizenodelist(n->npipe.cmdlist);
+	    break;
+      case NREDIR:
+      case NBACKGND:
+      case NSUBSHELL:
+	    calcsize(n->nredir.redirect);
+	    calcsize(n->nredir.n);
+	    break;
+      case NIF:
+	    calcsize(n->nif.elsepart);
+	    calcsize(n->nif.ifpart);
+	    calcsize(n->nif.test);
+	    break;
+      case NFOR:
+	    funcstringsize += strlen(n->nfor.var) + 1;
+	    calcsize(n->nfor.body);
+	    calcsize(n->nfor.args);
+	    break;
+      case NCASE:
+	    calcsize(n->ncase.cases);
+	    calcsize(n->ncase.expr);
+	    break;
+      case NCLIST:
+      case NCLISTFALLTHRU:
+	    calcsize(n->nclist.body);
+	    calcsize(n->nclist.pattern);
+	    calcsize(n->nclist.next);
+	    break;
+      case NDEFUN:
+      case NARG:
+	    sizenodelist(n->narg.backquote);
+	    funcstringsize += strlen(n->narg.text) + 1;
+	    calcsize(n->narg.next);
+	    break;
+      case NTO:
+      case NFROM:
+      case NFROMTO:
+      case NAPPEND:
+      case NCLOBBER:
+	    calcsize(n->nfile.fname);
+	    calcsize(n->nfile.next);
+	    break;
+      case NTOFD:
+      case NFROMFD:
+	    calcsize(n->ndup.vname);
+	    calcsize(n->ndup.next);
+	    break;
+      case NHERE:
+      case NXHERE:
+	    calcsize(n->nhere.doc);
+	    calcsize(n->nhere.next);
+	    break;
+      case NNOT:
+	    calcsize(n->nnot.com);
+	    break;
+      };
+}
+
+
+
+static void
+sizenodelist(struct nodelist *lp)
+{
+	while (lp) {
+		funcblocksize += ALIGN(sizeof(struct nodelist));
+		calcsize(lp->n);
+		lp = lp->next;
+	}
+}
+
+
+
+static union node *
+copynode(union node *n)
+{
+	union node *new;
+
+      if (n == NULL)
+	    return NULL;
+      new = funcblock;
+      funcblock = (char *)funcblock + nodesize[n->type];
+      switch (n->type) {
+      case NSEMI:
+      case NAND:
+      case NOR:
+      case NWHILE:
+      case NUNTIL:
+	    new->nbinary.ch2 = copynode(n->nbinary.ch2);
+	    new->nbinary.ch1 = copynode(n->nbinary.ch1);
+	    break;
+      case NCMD:
+	    new->ncmd.redirect = copynode(n->ncmd.redirect);
+	    new->ncmd.args = copynode(n->ncmd.args);
+	    break;
+      case NPIPE:
+	    new->npipe.cmdlist = copynodelist(n->npipe.cmdlist);
+	    new->npipe.backgnd = n->npipe.backgnd;
+	    break;
+      case NREDIR:
+      case NBACKGND:
+      case NSUBSHELL:
+	    new->nredir.redirect = copynode(n->nredir.redirect);
+	    new->nredir.n = copynode(n->nredir.n);
+	    break;
+      case NIF:
+	    new->nif.elsepart = copynode(n->nif.elsepart);
+	    new->nif.ifpart = copynode(n->nif.ifpart);
+	    new->nif.test = copynode(n->nif.test);
+	    break;
+      case NFOR:
+	    new->nfor.var = nodesavestr(n->nfor.var);
+	    new->nfor.body = copynode(n->nfor.body);
+	    new->nfor.args = copynode(n->nfor.args);
+	    break;
+      case NCASE:
+	    new->ncase.cases = copynode(n->ncase.cases);
+	    new->ncase.expr = copynode(n->ncase.expr);
+	    break;
+      case NCLIST:
+      case NCLISTFALLTHRU:
+	    new->nclist.body = copynode(n->nclist.body);
+	    new->nclist.pattern = copynode(n->nclist.pattern);
+	    new->nclist.next = copynode(n->nclist.next);
+	    break;
+      case NDEFUN:
+      case NARG:
+	    new->narg.backquote = copynodelist(n->narg.backquote);
+	    new->narg.text = nodesavestr(n->narg.text);
+	    new->narg.next = copynode(n->narg.next);
+	    break;
+      case NTO:
+      case NFROM:
+      case NFROMTO:
+      case NAPPEND:
+      case NCLOBBER:
+	    new->nfile.fname = copynode(n->nfile.fname);
+	    new->nfile.next = copynode(n->nfile.next);
+	    new->nfile.fd = n->nfile.fd;
+	    break;
+      case NTOFD:
+      case NFROMFD:
+	    new->ndup.vname = copynode(n->ndup.vname);
+	    new->ndup.dupfd = n->ndup.dupfd;
+	    new->ndup.next = copynode(n->ndup.next);
+	    new->ndup.fd = n->ndup.fd;
+	    break;
+      case NHERE:
+      case NXHERE:
+	    new->nhere.doc = copynode(n->nhere.doc);
+	    new->nhere.next = copynode(n->nhere.next);
+	    new->nhere.fd = n->nhere.fd;
+	    break;
+      case NNOT:
+	    new->nnot.com = copynode(n->nnot.com);
+	    break;
+      };
+      new->type = n->type;
+	return new;
+}
+
+
+static struct nodelist *
+copynodelist(struct nodelist *lp)
+{
+	struct nodelist *start;
+	struct nodelist **lpp;
+
+	lpp = &start;
+	while (lp) {
+		*lpp = funcblock;
+		funcblock = (char *)funcblock + ALIGN(sizeof(struct nodelist));
+		(*lpp)->n = copynode(lp->n);
+		lp = lp->next;
+		lpp = &(*lpp)->next;
+	}
+	*lpp = NULL;
+	return start;
+}
+
+
+
+static char *
+nodesavestr(const char *s)
+{
+	const char *p = s;
+	char *q = funcstring;
+	char   *rtn = funcstring;
+
+	while ((*q++ = *p++) != '\0')
+		continue;
+	funcstring = q;
+	return rtn;
+}
+
+
+void
+reffunc(struct funcdef *fn)
+{
+	if (fn)
+		fn->refcount++;
+}
+
+
+/*
+ * Decrement the reference count of a function definition, freeing it
+ * if it falls to 0.
+ */
+
+void
+unreffunc(struct funcdef *fn)
+{
+	if (fn) {
+		fn->refcount--;
+		if (fn->refcount > 0)
+			return;
+		ckfree(fn);
+	}
+}
diff --git a/external/sh/nodes.h b/external/sh/nodes.h
new file mode 100644
index 00000000..dddbf609
--- /dev/null
+++ b/external/sh/nodes.h
@@ -0,0 +1,163 @@
+/*
+ * This file was generated by the mknodes program.
+ */
+
+#define NSEMI 0
+#define NCMD 1
+#define NPIPE 2
+#define NREDIR 3
+#define NBACKGND 4
+#define NSUBSHELL 5
+#define NAND 6
+#define NOR 7
+#define NIF 8
+#define NWHILE 9
+#define NUNTIL 10
+#define NFOR 11
+#define NCASE 12
+#define NCLIST 13
+#define NCLISTFALLTHRU 14
+#define NDEFUN 15
+#define NARG 16
+#define NTO 17
+#define NFROM 18
+#define NFROMTO 19
+#define NAPPEND 20
+#define NCLOBBER 21
+#define NTOFD 22
+#define NFROMFD 23
+#define NHERE 24
+#define NXHERE 25
+#define NNOT 26
+
+
+
+struct nbinary {
+      int type;
+      union node *ch1;
+      union node *ch2;
+};
+
+
+struct ncmd {
+      int type;
+      union node *args;
+      union node *redirect;
+};
+
+
+struct npipe {
+      int type;
+      int backgnd;
+      struct nodelist *cmdlist;
+};
+
+
+struct nredir {
+      int type;
+      union node *n;
+      union node *redirect;
+};
+
+
+struct nif {
+      int type;
+      union node *test;
+      union node *ifpart;
+      union node *elsepart;
+};
+
+
+struct nfor {
+      int type;
+      union node *args;
+      union node *body;
+      char *var;
+};
+
+
+struct ncase {
+      int type;
+      union node *expr;
+      union node *cases;
+};
+
+
+struct nclist {
+      int type;
+      union node *next;
+      union node *pattern;
+      union node *body;
+};
+
+
+struct narg {
+      int type;
+      union node *next;
+      char *text;
+      struct nodelist *backquote;
+};
+
+
+struct nfile {
+      int type;
+      int fd;
+      union node *next;
+      union node *fname;
+      char *expfname;
+};
+
+
+struct ndup {
+      int type;
+      int fd;
+      union node *next;
+      int dupfd;
+      union node *vname;
+};
+
+
+struct nhere {
+      int type;
+      int fd;
+      union node *next;
+      union node *doc;
+      const char *expdoc;
+};
+
+
+struct nnot {
+      int type;
+      union node *com;
+};
+
+
+union node {
+      int type;
+      struct nbinary nbinary;
+      struct ncmd ncmd;
+      struct npipe npipe;
+      struct nredir nredir;
+      struct nif nif;
+      struct nfor nfor;
+      struct ncase ncase;
+      struct nclist nclist;
+      struct narg narg;
+      struct nfile nfile;
+      struct ndup ndup;
+      struct nhere nhere;
+      struct nnot nnot;
+};
+
+
+struct nodelist {
+	struct nodelist *next;
+	union node *n;
+};
+
+
+struct funcdef;
+struct funcdef *copyfunc(union node *);
+union node *getfuncnode(struct funcdef *);
+void reffunc(struct funcdef *);
+void unreffunc(struct funcdef *);
diff --git a/external/sh/options.c b/external/sh/options.c
new file mode 100644
index 00000000..f12ec40f
--- /dev/null
+++ b/external/sh/options.c
@@ -0,0 +1,588 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)options.c	8.2 (Berkeley) 5/4/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: head/bin/sh/options.c 279508 2015-03-01 22:32:23Z jilles $");
+
+#include <signal.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+#include "shell.h"
+#define DEFINE_OPTIONS
+#include "options.h"
+#undef DEFINE_OPTIONS
+#include "nodes.h"	/* for other header files */
+#include "eval.h"
+#include "jobs.h"
+#include "input.h"
+#include "output.h"
+#include "trap.h"
+#include "var.h"
+#include "memalloc.h"
+#include "error.h"
+#include "mystring.h"
+#include "builtins.h"
+#ifndef NO_HISTORY
+#include "myhistedit.h"
+#endif
+
+char *arg0;			/* value of $0 */
+struct shparam shellparam;	/* current positional parameters */
+char **argptr;			/* argument list for builtin commands */
+char *shoptarg;			/* set by nextopt (like getopt) */
+char *nextopt_optptr;		/* used by nextopt */
+
+char *minusc;			/* argument to -c option */
+
+
+static void options(int);
+static void minus_o(char *, int);
+static void setoption(int, int);
+static int getopts(char *, char *, char **, char ***, char **);
+
+
+/*
+ * Process the shell command line arguments.
+ */
+
+void
+procargs(int argc, char **argv)
+{
+	int i;
+	char *scriptname;
+
+	argptr = argv;
+	if (argc > 0)
+		argptr++;
+	for (i = 0; i < NOPTS; i++)
+		optlist[i].val = 2;
+	privileged = (getuid() != geteuid() || getgid() != getegid());
+	options(1);
+	if (*argptr == NULL && minusc == NULL)
+		sflag = 1;
+	if (iflag != 0 && sflag == 1 && isatty(0) && isatty(1)) {
+		iflag = 1;
+		if (Eflag == 2)
+			Eflag = 1;
+	}
+	if (mflag == 2)
+		mflag = iflag;
+	for (i = 0; i < NOPTS; i++)
+		if (optlist[i].val == 2)
+			optlist[i].val = 0;
+	arg0 = argv[0];
+	if (sflag == 0 && minusc == NULL) {
+		scriptname = *argptr++;
+		setinputfile(scriptname, 0);
+		commandname = arg0 = scriptname;
+	}
+	/* POSIX 1003.2: first arg after -c cmd is $0, remainder $1... */
+	if (argptr && minusc && *argptr)
+		arg0 = *argptr++;
+
+	shellparam.p = argptr;
+	shellparam.reset = 1;
+	/* assert(shellparam.malloc == 0 && shellparam.nparam == 0); */
+	while (*argptr) {
+		shellparam.nparam++;
+		argptr++;
+	}
+	optschanged();
+}
+
+
+void
+optschanged(void)
+{
+	setinteractive(iflag);
+#ifndef NO_HISTORY
+	histedit();
+#endif
+	setjobctl(mflag);
+}
+
+/*
+ * Process shell options.  The global variable argptr contains a pointer
+ * to the argument list; we advance it past the options.
+ */
+
+static void
+options(int cmdline)
+{
+	char *kp, *p;
+	int val;
+	int c;
+
+	if (cmdline)
+		minusc = NULL;
+	while ((p = *argptr) != NULL) {
+		argptr++;
+		if ((c = *p++) == '-') {
+			val = 1;
+			/* A "-" or  "--" terminates options */
+			if (p[0] == '\0')
+				goto end_options1;
+			if (p[0] == '-' && p[1] == '\0')
+				goto end_options2;
+			/**
+			 * For the benefit of `#!' lines in shell scripts,
+			 * treat a string of '-- *#.*' the same as '--'.
+			 * This is needed so that a script starting with:
+			 *	#!/bin/sh -- # -*- perl -*-
+			 * will continue to work after a change is made to
+			 * kern/imgact_shell.c to NOT token-ize the options
+			 * specified on a '#!' line.  A bit of a kludge,
+			 * but that trick is recommended in documentation
+			 * for some scripting languages, and we might as
+			 * well continue to support it.
+			 */
+			if (p[0] == '-') {
+				kp = p + 1;
+				while (*kp == ' ' || *kp == '\t')
+					kp++;
+				if (*kp == '#' || *kp == '\0')
+					goto end_options2;
+			}
+		} else if (c == '+') {
+			val = 0;
+		} else {
+			argptr--;
+			break;
+		}
+		while ((c = *p++) != '\0') {
+			if (c == 'c' && cmdline) {
+				char *q;
+#ifdef NOHACK	/* removing this code allows sh -ce 'foo' for compat */
+				if (*p == '\0')
+#endif
+					q = *argptr++;
+				if (q == NULL || minusc != NULL)
+					error("Bad -c option");
+				minusc = q;
+#ifdef NOHACK
+				break;
+#endif
+			} else if (c == 'o') {
+				minus_o(*argptr, val);
+				if (*argptr)
+					argptr++;
+			} else
+				setoption(c, val);
+		}
+	}
+	return;
+
+	/* When processing `set', a single "-" means turn off -x and -v */
+end_options1:
+	if (!cmdline) {
+		xflag = vflag = 0;
+		return;
+	}
+
+	/*
+	 * When processing `set', a "--" means the remaining arguments
+	 * replace the positional parameters in the active shell.  If
+	 * there are no remaining options, then all the positional
+	 * parameters are cleared (equivalent to doing ``shift $#'').
+	 */
+end_options2:
+	if (!cmdline) {
+		if (*argptr == NULL)
+			setparam(argptr);
+		return;
+	}
+
+	/*
+	 * At this point we are processing options given to 'sh' on a command
+	 * line.  If an end-of-options marker ("-" or "--") is followed by an
+	 * arg of "#", then skip over all remaining arguments.  Some scripting
+	 * languages (e.g.: perl) document that /bin/sh will implement this
+	 * behavior, and they recommend that users take advantage of it to
+	 * solve certain issues that can come up when writing a perl script.
+	 * Yes, this feature is in /bin/sh to help users write perl scripts.
+	 */
+	p = *argptr;
+	if (p != NULL && p[0] == '#' && p[1] == '\0') {
+		while (*argptr != NULL)
+			argptr++;
+		/* We need to keep the final argument */
+		argptr--;
+	}
+}
+
+static void
+minus_o(char *name, int val)
+{
+	int i;
+
+	if (name == NULL) {
+		if (val) {
+			/* "Pretty" output. */
+			out1str("Current option settings\n");
+			for (i = 0; i < NOPTS; i++)
+				out1fmt("%-16s%s\n", optlist[i].name,
+					optlist[i].val ? "on" : "off");
+		} else {
+			/* Output suitable for re-input to shell. */
+			for (i = 0; i < NOPTS; i++)
+				out1fmt("%s %co %s%s",
+				    i % 6 == 0 ? "set" : "",
+				    optlist[i].val ? '-' : '+',
+				    optlist[i].name,
+				    i % 6 == 5 || i == NOPTS - 1 ? "\n" : "");
+		}
+	} else {
+		for (i = 0; i < NOPTS; i++)
+			if (equal(name, optlist[i].name)) {
+				setoption(optlist[i].letter, val);
+				return;
+			}
+		error("Illegal option -o %s", name);
+	}
+}
+
+
+static void
+setoption(int flag, int val)
+{
+	int i;
+
+	if (flag == 'p' && !val && privileged) {
+		if (setgid(getgid()) == -1)
+			error("setgid");
+		if (setuid(getuid()) == -1)
+			error("setuid");
+	}
+	for (i = 0; i < NOPTS; i++)
+		if (optlist[i].letter == flag) {
+			optlist[i].val = val;
+			if (val) {
+				/* #%$ hack for ksh semantics */
+				if (flag == 'V')
+					Eflag = 0;
+				else if (flag == 'E')
+					Vflag = 0;
+			}
+			return;
+		}
+	error("Illegal option -%c", flag);
+}
+
+
+/*
+ * Set the shell parameters.
+ */
+
+void
+setparam(char **argv)
+{
+	char **newparam;
+	char **ap;
+	int nparam;
+
+	for (nparam = 0 ; argv[nparam] ; nparam++);
+	ap = newparam = ckmalloc((nparam + 1) * sizeof *ap);
+	while (*argv) {
+		*ap++ = savestr(*argv++);
+	}
+	*ap = NULL;
+	freeparam(&shellparam);
+	shellparam.malloc = 1;
+	shellparam.nparam = nparam;
+	shellparam.p = newparam;
+	shellparam.optp = NULL;
+	shellparam.reset = 1;
+	shellparam.optnext = NULL;
+}
+
+
+/*
+ * Free the list of positional parameters.
+ */
+
+void
+freeparam(struct shparam *param)
+{
+	char **ap;
+
+	if (param->malloc) {
+		for (ap = param->p ; *ap ; ap++)
+			ckfree(*ap);
+		ckfree(param->p);
+	}
+	if (param->optp) {
+		for (ap = param->optp ; *ap ; ap++)
+			ckfree(*ap);
+		ckfree(param->optp);
+	}
+}
+
+
+
+/*
+ * The shift builtin command.
+ */
+
+int
+shiftcmd(int argc, char **argv)
+{
+	int n;
+	char **ap1, **ap2;
+
+	n = 1;
+	if (argc > 1)
+		n = number(argv[1]);
+	if (n > shellparam.nparam)
+		return 1;
+	INTOFF;
+	shellparam.nparam -= n;
+	for (ap1 = shellparam.p ; --n >= 0 ; ap1++) {
+		if (shellparam.malloc)
+			ckfree(*ap1);
+	}
+	ap2 = shellparam.p;
+	while ((*ap2++ = *ap1++) != NULL);
+	shellparam.reset = 1;
+	INTON;
+	return 0;
+}
+
+
+
+/*
+ * The set command builtin.
+ */
+
+int
+setcmd(int argc, char **argv)
+{
+	if (argc == 1)
+		return showvarscmd(argc, argv);
+	INTOFF;
+	options(0);
+	optschanged();
+	if (*argptr != NULL) {
+		setparam(argptr);
+	}
+	INTON;
+	return 0;
+}
+
+
+void
+getoptsreset(const char *value)
+{
+	while (*value == '0')
+		value++;
+	if (strcmp(value, "1") == 0)
+		shellparam.reset = 1;
+}
+
+/*
+ * The getopts builtin.  Shellparam.optnext points to the next argument
+ * to be processed.  Shellparam.optptr points to the next character to
+ * be processed in the current argument.  If shellparam.optnext is NULL,
+ * then it's the first time getopts has been called.
+ */
+
+int
+getoptscmd(int argc, char **argv)
+{
+	char **optbase = NULL, **ap;
+	int i;
+
+	if (argc < 3)
+		error("usage: getopts optstring var [arg]");
+
+	if (shellparam.reset == 1) {
+		INTOFF;
+		if (shellparam.optp) {
+			for (ap = shellparam.optp ; *ap ; ap++)
+				ckfree(*ap);
+			ckfree(shellparam.optp);
+			shellparam.optp = NULL;
+		}
+		if (argc > 3) {
+			shellparam.optp = ckmalloc((argc - 2) * sizeof *ap);
+			memset(shellparam.optp, '\0', (argc - 2) * sizeof *ap);
+			for (i = 0; i < argc - 3; i++)
+				shellparam.optp[i] = savestr(argv[i + 3]);
+		}
+		INTON;
+		optbase = argc == 3 ? shellparam.p : shellparam.optp;
+		shellparam.optnext = optbase;
+		shellparam.optptr = NULL;
+		shellparam.reset = 0;
+	} else
+		optbase = shellparam.optp ? shellparam.optp : shellparam.p;
+
+	return getopts(argv[1], argv[2], optbase, &shellparam.optnext,
+		       &shellparam.optptr);
+}
+
+static int
+getopts(char *optstr, char *optvar, char **optfirst, char ***optnext,
+    char **optptr)
+{
+	char *p, *q;
+	char c = '?';
+	int done = 0;
+	int ind = 0;
+	int err = 0;
+	char s[10];
+	const char *newoptarg = NULL;
+
+	if ((p = *optptr) == NULL || *p == '\0') {
+		/* Current word is done, advance */
+		if (*optnext == NULL)
+			return 1;
+		p = **optnext;
+		if (p == NULL || *p != '-' || *++p == '\0') {
+atend:
+			ind = *optnext - optfirst + 1;
+			*optnext = NULL;
+			p = NULL;
+			done = 1;
+			goto out;
+		}
+		(*optnext)++;
+		if (p[0] == '-' && p[1] == '\0')	/* check for "--" */
+			goto atend;
+	}
+
+	c = *p++;
+	for (q = optstr; *q != c; ) {
+		if (*q == '\0') {
+			if (optstr[0] == ':') {
+				s[0] = c;
+				s[1] = '\0';
+				newoptarg = s;
+			}
+			else
+				out2fmt_flush("Illegal option -%c\n", c);
+			c = '?';
+			goto out;
+		}
+		if (*++q == ':')
+			q++;
+	}
+
+	if (*++q == ':') {
+		if (*p == '\0' && (p = **optnext) == NULL) {
+			if (optstr[0] == ':') {
+				s[0] = c;
+				s[1] = '\0';
+				newoptarg = s;
+				c = ':';
+			}
+			else {
+				out2fmt_flush("No arg for -%c option\n", c);
+				c = '?';
+			}
+			goto out;
+		}
+
+		if (p == **optnext)
+			(*optnext)++;
+		newoptarg = p;
+		p = NULL;
+	}
+
+out:
+	if (*optnext != NULL)
+		ind = *optnext - optfirst + 1;
+	*optptr = p;
+	if (newoptarg != NULL)
+		err |= setvarsafe("OPTARG", newoptarg, 0);
+	else {
+		INTOFF;
+		err |= unsetvar("OPTARG");
+		INTON;
+	}
+	fmtstr(s, sizeof(s), "%d", ind);
+	err |= setvarsafe("OPTIND", s, VNOFUNC);
+	s[0] = c;
+	s[1] = '\0';
+	err |= setvarsafe(optvar, s, 0);
+	if (err) {
+		*optnext = NULL;
+		*optptr = NULL;
+		flushall();
+		exraise(EXERROR);
+	}
+	return done;
+}
+
+/*
+ * Standard option processing (a la getopt) for builtin routines.  The
+ * only argument that is passed to nextopt is the option string; the
+ * other arguments are unnecessary.  It return the character, or '\0' on
+ * end of input.
+ */
+
+int
+nextopt(const char *optstring)
+{
+	char *p;
+	const char *q;
+	char c;
+
+	if ((p = nextopt_optptr) == NULL || *p == '\0') {
+		p = *argptr;
+		if (p == NULL || *p != '-' || *++p == '\0')
+			return '\0';
+		argptr++;
+		if (p[0] == '-' && p[1] == '\0')	/* check for "--" */
+			return '\0';
+	}
+	c = *p++;
+	for (q = optstring ; *q != c ; ) {
+		if (*q == '\0')
+			error("Illegal option -%c", c);
+		if (*++q == ':')
+			q++;
+	}
+	if (*++q == ':') {
+		if (*p == '\0' && (p = *argptr++) == NULL)
+			error("No arg for -%c option", c);
+		shoptarg = p;
+		p = NULL;
+	}
+	nextopt_optptr = p;
+	return c;
+}
diff --git a/external/sh/options.h b/external/sh/options.h
new file mode 100644
index 00000000..4e06bf02
--- /dev/null
+++ b/external/sh/options.h
@@ -0,0 +1,114 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)options.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: head/bin/sh/options.h 279503 2015-03-01 21:46:55Z jilles $
+ */
+
+struct shparam {
+	int nparam;		/* # of positional parameters (without $0) */
+	unsigned char malloc;	/* if parameter list dynamically allocated */
+	unsigned char reset;	/* if getopts has been reset */
+	char **p;		/* parameter list */
+	char **optp;		/* parameter list for getopts */
+	char **optnext;		/* next parameter to be processed by getopts */
+	char *optptr;		/* used by getopts */
+};
+
+
+
+#define eflag optlist[0].val
+#define fflag optlist[1].val
+#define Iflag optlist[2].val
+#define iflag optlist[3].val
+#define mflag optlist[4].val
+#define nflag optlist[5].val
+#define sflag optlist[6].val
+#define xflag optlist[7].val
+#define vflag optlist[8].val
+#define Vflag optlist[9].val
+#define	Eflag optlist[10].val
+#define	Cflag optlist[11].val
+#define	aflag optlist[12].val
+#define	bflag optlist[13].val
+#define	uflag optlist[14].val
+#define	privileged optlist[15].val
+#define	Tflag optlist[16].val
+#define	Pflag optlist[17].val
+#define	hflag optlist[18].val
+
+#define NOPTS	19
+
+struct optent {
+	const char *name;
+	const char letter;
+	char val;
+};
+
+extern struct optent optlist[NOPTS];
+#ifdef DEFINE_OPTIONS
+struct optent optlist[NOPTS] = {
+	{ "errexit",	'e',	0 },
+	{ "noglob",	'f',	0 },
+	{ "ignoreeof",	'I',	0 },
+	{ "interactive",'i',	0 },
+	{ "monitor",	'm',	0 },
+	{ "noexec",	'n',	0 },
+	{ "stdin",	's',	0 },
+	{ "xtrace",	'x',	0 },
+	{ "verbose",	'v',	0 },
+	{ "vi",		'V',	0 },
+	{ "emacs",	'E',	0 },
+	{ "noclobber",	'C',	0 },
+	{ "allexport",	'a',	0 },
+	{ "notify",	'b',	0 },
+	{ "nounset",	'u',	0 },
+	{ "privileged",	'p',	0 },
+	{ "trapsasync",	'T',	0 },
+	{ "physical",	'P',	0 },
+	{ "trackall",	'h',	0 },
+};
+#endif
+
+
+extern char *minusc;		/* argument to -c option */
+extern char *arg0;		/* $0 */
+extern struct shparam shellparam;  /* $@ */
+extern char **argptr;		/* argument list for builtin commands */
+extern char *shoptarg;		/* set by nextopt */
+extern char *nextopt_optptr;	/* used by nextopt */
+
+void procargs(int, char **);
+void optschanged(void);
+void setparam(char **);
+void freeparam(struct shparam *);
+int nextopt(const char *);
+void getoptsreset(const char *);
diff --git a/external/sh/output.c b/external/sh/output.c
new file mode 100644
index 00000000..77186035
--- /dev/null
+++ b/external/sh/output.c
@@ -0,0 +1,375 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)output.c	8.2 (Berkeley) 5/4/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: head/bin/sh/output.c 275766 2014-12-14 16:26:19Z jilles $");
+
+/*
+ * Shell output routines.  We use our own output routines because:
+ *	When a builtin command is interrupted we have to discard
+ *		any pending output.
+ *	When a builtin command appears in back quotes, we want to
+ *		save the output of the command in a region obtained
+ *		via malloc, rather than doing a fork and reading the
+ *		output of the command via a pipe.
+ */
+
+#include <stdio.h>	/* defines BUFSIZ */
+#include <string.h>
+#include <stdarg.h>
+#include <errno.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <wchar.h>
+#include <wctype.h>
+
+#include "shell.h"
+#include "syntax.h"
+#include "output.h"
+#include "memalloc.h"
+#include "error.h"
+#include "var.h"
+
+
+#define OUTBUFSIZ BUFSIZ
+#define MEM_OUT -2		/* output to dynamically allocated memory */
+#define OUTPUT_ERR 01		/* error occurred on output */
+
+static int doformat_wr(void *, const char *, int);
+
+struct output output = {NULL, 0, NULL, OUTBUFSIZ, 1, 0};
+struct output errout = {NULL, 0, NULL, 256, 2, 0};
+struct output memout = {NULL, 0, NULL, 0, MEM_OUT, 0};
+struct output *out1 = &output;
+struct output *out2 = &errout;
+
+void
+outcslow(int c, struct output *file)
+{
+	outc(c, file);
+}
+
+void
+out1str(const char *p)
+{
+	outstr(p, out1);
+}
+
+void
+out1qstr(const char *p)
+{
+	outqstr(p, out1);
+}
+
+void
+out2str(const char *p)
+{
+	outstr(p, out2);
+}
+
+void
+out2qstr(const char *p)
+{
+	outqstr(p, out2);
+}
+
+void
+outstr(const char *p, struct output *file)
+{
+	outbin(p, strlen(p), file);
+}
+
+static void
+byteseq(int ch, struct output *file)
+{
+	char seq[4];
+
+	seq[0] = '\\';
+	seq[1] = (ch >> 6 & 0x3) + '0';
+	seq[2] = (ch >> 3 & 0x7) + '0';
+	seq[3] = (ch & 0x7) + '0';
+	outbin(seq, 4, file);
+}
+
+static void
+outdqstr(const char *p, struct output *file)
+{
+	const char *end;
+	mbstate_t mbs;
+	size_t clen;
+	wchar_t wc;
+
+	memset(&mbs, '\0', sizeof(mbs));
+	end = p + strlen(p);
+	outstr("$'", file);
+	while ((clen = mbrtowc(&wc, p, end - p + 1, &mbs)) != 0) {
+		if (clen == (size_t)-2) {
+			while (p < end)
+				byteseq(*p++, file);
+			break;
+		}
+		if (clen == (size_t)-1) {
+			memset(&mbs, '\0', sizeof(mbs));
+			byteseq(*p++, file);
+			continue;
+		}
+		if (wc == L'\n')
+			outcslow('\n', file), p++;
+		else if (wc == L'\r')
+			outstr("\\r", file), p++;
+		else if (wc == L'\t')
+			outstr("\\t", file), p++;
+		else if (!iswprint(wc)) {
+			for (; clen > 0; clen--)
+				byteseq(*p++, file);
+		} else {
+			if (wc == L'\'' || wc == L'\\')
+				outcslow('\\', file);
+			outbin(p, clen, file);
+			p += clen;
+		}
+	}
+	outcslow('\'', file);
+}
+
+/* Like outstr(), but quote for re-input into the shell. */
+void
+outqstr(const char *p, struct output *file)
+{
+	int i;
+
+	if (p[0] == '\0') {
+		outstr("''", file);
+		return;
+	}
+	for (i = 0; p[i] != '\0'; i++) {
+		if ((p[i] > '\0' && p[i] < ' ' && p[i] != '\n') ||
+		    (p[i] & 0x80) != 0 || p[i] == '\'') {
+			outdqstr(p, file);
+			return;
+		}
+	}
+
+	if (p[strcspn(p, "|&;<>()$`\\\" \n*?[~#=")] == '\0' ||
+			strcmp(p, "[") == 0) {
+		outstr(p, file);
+		return;
+	}
+
+	outcslow('\'', file);
+	outstr(p, file);
+	outcslow('\'', file);
+}
+
+void
+outbin(const void *data, size_t len, struct output *file)
+{
+	const char *p;
+
+	p = data;
+	while (len-- > 0)
+		outc(*p++, file);
+}
+
+void
+emptyoutbuf(struct output *dest)
+{
+	int offset;
+
+	if (dest->buf == NULL) {
+		INTOFF;
+		dest->buf = ckmalloc(dest->bufsize);
+		dest->nextc = dest->buf;
+		dest->nleft = dest->bufsize;
+		INTON;
+	} else if (dest->fd == MEM_OUT) {
+		offset = dest->bufsize;
+		INTOFF;
+		dest->bufsize <<= 1;
+		dest->buf = ckrealloc(dest->buf, dest->bufsize);
+		dest->nleft = dest->bufsize - offset;
+		dest->nextc = dest->buf + offset;
+		INTON;
+	} else {
+		flushout(dest);
+	}
+	dest->nleft--;
+}
+
+
+void
+flushall(void)
+{
+	flushout(&output);
+	flushout(&errout);
+}
+
+
+void
+flushout(struct output *dest)
+{
+
+	if (dest->buf == NULL || dest->nextc == dest->buf || dest->fd < 0)
+		return;
+	if (xwrite(dest->fd, dest->buf, dest->nextc - dest->buf) < 0)
+		dest->flags |= OUTPUT_ERR;
+	dest->nextc = dest->buf;
+	dest->nleft = dest->bufsize;
+}
+
+
+void
+freestdout(void)
+{
+	INTOFF;
+	if (output.buf) {
+		ckfree(output.buf);
+		output.buf = NULL;
+		output.nleft = 0;
+	}
+	INTON;
+}
+
+
+int
+outiserror(struct output *file)
+{
+	return (file->flags & OUTPUT_ERR);
+}
+
+
+void
+outclearerror(struct output *file)
+{
+	file->flags &= ~OUTPUT_ERR;
+}
+
+
+void
+outfmt(struct output *file, const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	doformat(file, fmt, ap);
+	va_end(ap);
+}
+
+
+void
+out1fmt(const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	doformat(out1, fmt, ap);
+	va_end(ap);
+}
+
+void
+out2fmt_flush(const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	doformat(out2, fmt, ap);
+	va_end(ap);
+	flushout(out2);
+}
+
+void
+fmtstr(char *outbuf, int length, const char *fmt, ...)
+{
+	va_list ap;
+
+	INTOFF;
+	va_start(ap, fmt);
+	vsnprintf(outbuf, length, fmt, ap);
+	va_end(ap);
+	INTON;
+}
+
+static int
+doformat_wr(void *cookie, const char *buf, int len)
+{
+	struct output *o;
+
+	o = (struct output *)cookie;
+	outbin(buf, len, o);
+
+	return (len);
+}
+
+void
+doformat(struct output *dest, const char *f, va_list ap)
+{
+	FILE *fp;
+
+	if ((fp = fwopen(dest, doformat_wr)) != NULL) {
+		vfprintf(fp, f, ap);
+		fclose(fp);
+	}
+}
+
+/*
+ * Version of write which resumes after a signal is caught.
+ */
+
+int
+xwrite(int fd, const char *buf, int nbytes)
+{
+	int ntry;
+	int i;
+	int n;
+
+	n = nbytes;
+	ntry = 0;
+	for (;;) {
+		i = write(fd, buf, n);
+		if (i > 0) {
+			if ((n -= i) <= 0)
+				return nbytes;
+			buf += i;
+			ntry = 0;
+		} else if (i == 0) {
+			if (++ntry > 10)
+				return nbytes - n;
+		} else if (errno != EINTR) {
+			return -1;
+		}
+	}
+}
diff --git a/external/sh/output.h b/external/sh/output.h
new file mode 100644
index 00000000..227db2dc
--- /dev/null
+++ b/external/sh/output.h
@@ -0,0 +1,83 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)output.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: head/bin/sh/output.h 244162 2012-12-12 22:01:10Z jilles $
+ */
+
+#ifndef OUTPUT_INCL
+
+#include <stdarg.h>
+#include <stddef.h>
+
+struct output {
+	char *nextc;
+	int nleft;
+	char *buf;
+	int bufsize;
+	short fd;
+	short flags;
+};
+
+extern struct output output; /* to fd 1 */
+extern struct output errout; /* to fd 2 */
+extern struct output memout;
+extern struct output *out1; /* &memout if backquote, otherwise &output */
+extern struct output *out2; /* &memout if backquote with 2>&1, otherwise
+			       &errout */
+
+void outcslow(int, struct output *);
+void out1str(const char *);
+void out1qstr(const char *);
+void out2str(const char *);
+void out2qstr(const char *);
+void outstr(const char *, struct output *);
+void outqstr(const char *, struct output *);
+void outbin(const void *, size_t, struct output *);
+void emptyoutbuf(struct output *);
+void flushall(void);
+void flushout(struct output *);
+void freestdout(void);
+int outiserror(struct output *);
+void outclearerror(struct output *);
+void outfmt(struct output *, const char *, ...) __printflike(2, 3);
+void out1fmt(const char *, ...) __printflike(1, 2);
+void out2fmt_flush(const char *, ...) __printflike(1, 2);
+void fmtstr(char *, int, const char *, ...) __printflike(3, 4);
+void doformat(struct output *, const char *, va_list) __printflike(2, 0);
+int xwrite(int, const char *, int);
+
+#define outc(c, file)	(--(file)->nleft < 0? (emptyoutbuf(file), *(file)->nextc++ = (c)) : (*(file)->nextc++ = (c)))
+#define out1c(c)	outc(c, out1);
+#define out2c(c)	outcslow(c, out2);
+
+#define OUTPUT_INCL
+#endif
diff --git a/external/sh/parser.c b/external/sh/parser.c
new file mode 100644
index 00000000..657637cd
--- /dev/null
+++ b/external/sh/parser.c
@@ -0,0 +1,2072 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)parser.c	8.7 (Berkeley) 5/16/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: head/bin/sh/parser.c 278820 2015-02-15 21:47:43Z jilles $");
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdio.h>
+
+#include "shell.h"
+#include "parser.h"
+#include "nodes.h"
+#include "expand.h"	/* defines rmescapes() */
+#include "syntax.h"
+#include "options.h"
+#include "input.h"
+#include "output.h"
+#include "var.h"
+#include "error.h"
+#include "memalloc.h"
+#include "mystring.h"
+#include "alias.h"
+#include "show.h"
+#include "eval.h"
+#include "exec.h"	/* to check for special builtins */
+#ifndef NO_HISTORY
+#include "myhistedit.h"
+#endif
+
+/*
+ * Shell command parser.
+ */
+
+#define	PROMPTLEN	128
+
+/* values of checkkwd variable */
+#define CHKALIAS	0x1
+#define CHKKWD		0x2
+#define CHKNL		0x4
+
+/* values returned by readtoken */
+#include "token.h"
+
+
+
+struct heredoc {
+	struct heredoc *next;	/* next here document in list */
+	union node *here;		/* redirection node */
+	char *eofmark;		/* string indicating end of input */
+	int striptabs;		/* if set, strip leading tabs */
+};
+
+struct parser_temp {
+	struct parser_temp *next;
+	void *data;
+};
+
+
+static struct heredoc *heredoclist;	/* list of here documents to read */
+static int doprompt;		/* if set, prompt the user */
+static int needprompt;		/* true if interactive and at start of line */
+static int lasttoken;		/* last token read */
+static int tokpushback;		/* last token pushed back */
+static char *wordtext;		/* text of last word returned by readtoken */
+static int checkkwd;
+static struct nodelist *backquotelist;
+static union node *redirnode;
+static struct heredoc *heredoc;
+static int quoteflag;		/* set if (part of) last token was quoted */
+static int startlinno;		/* line # where last token started */
+static int funclinno;		/* line # where the current function started */
+static struct parser_temp *parser_temp;
+
+
+static union node *list(int);
+static union node *andor(void);
+static union node *pipeline(void);
+static union node *command(void);
+static union node *simplecmd(union node **, union node *);
+static union node *makename(void);
+static union node *makebinary(int type, union node *n1, union node *n2);
+static void parsefname(void);
+static void parseheredoc(void);
+static int peektoken(void);
+static int readtoken(void);
+static int xxreadtoken(void);
+static int readtoken1(int, const char *, const char *, int);
+static int noexpand(char *);
+static void consumetoken(int);
+static void synexpect(int) __dead2;
+static void synerror(const char *) __dead2;
+static void setprompt(int);
+static int pgetc_linecont(void);
+
+
+static void *
+parser_temp_alloc(size_t len)
+{
+	struct parser_temp *t;
+
+	INTOFF;
+	t = ckmalloc(sizeof(*t));
+	t->data = NULL;
+	t->next = parser_temp;
+	parser_temp = t;
+	t->data = ckmalloc(len);
+	INTON;
+	return t->data;
+}
+
+
+static void *
+parser_temp_realloc(void *ptr, size_t len)
+{
+	struct parser_temp *t;
+
+	INTOFF;
+	t = parser_temp;
+	if (ptr != t->data)
+		error("bug: parser_temp_realloc misused");
+	t->data = ckrealloc(t->data, len);
+	INTON;
+	return t->data;
+}
+
+
+static void
+parser_temp_free_upto(void *ptr)
+{
+	struct parser_temp *t;
+	int done = 0;
+
+	INTOFF;
+	while (parser_temp != NULL && !done) {
+		t = parser_temp;
+		parser_temp = t->next;
+		done = t->data == ptr;
+		ckfree(t->data);
+		ckfree(t);
+	}
+	INTON;
+	if (!done)
+		error("bug: parser_temp_free_upto misused");
+}
+
+
+static void
+parser_temp_free_all(void)
+{
+	struct parser_temp *t;
+
+	INTOFF;
+	while (parser_temp != NULL) {
+		t = parser_temp;
+		parser_temp = t->next;
+		ckfree(t->data);
+		ckfree(t);
+	}
+	INTON;
+}
+
+
+/*
+ * Read and parse a command.  Returns NEOF on end of file.  (NULL is a
+ * valid parse tree indicating a blank line.)
+ */
+
+union node *
+parsecmd(int interact)
+{
+	int t;
+
+	/* This assumes the parser is not re-entered,
+	 * which could happen if we add command substitution on PS1/PS2.
+	 */
+	parser_temp_free_all();
+	heredoclist = NULL;
+
+	tokpushback = 0;
+	checkkwd = 0;
+	doprompt = interact;
+	if (doprompt)
+		setprompt(1);
+	else
+		setprompt(0);
+	needprompt = 0;
+	t = readtoken();
+	if (t == TEOF)
+		return NEOF;
+	if (t == TNL)
+		return NULL;
+	tokpushback++;
+	return list(1);
+}
+
+
+static union node *
+list(int nlflag)
+{
+	union node *ntop, *n1, *n2, *n3;
+	int tok;
+
+	checkkwd = CHKNL | CHKKWD | CHKALIAS;
+	if (!nlflag && tokendlist[peektoken()])
+		return NULL;
+	ntop = n1 = NULL;
+	for (;;) {
+		n2 = andor();
+		tok = readtoken();
+		if (tok == TBACKGND) {
+			if (n2 != NULL && n2->type == NPIPE) {
+				n2->npipe.backgnd = 1;
+			} else if (n2 != NULL && n2->type == NREDIR) {
+				n2->type = NBACKGND;
+			} else {
+				n3 = (union node *)stalloc(sizeof (struct nredir));
+				n3->type = NBACKGND;
+				n3->nredir.n = n2;
+				n3->nredir.redirect = NULL;
+				n2 = n3;
+			}
+		}
+		if (ntop == NULL)
+			ntop = n2;
+		else if (n1 == NULL) {
+			n1 = makebinary(NSEMI, ntop, n2);
+			ntop = n1;
+		}
+		else {
+			n3 = makebinary(NSEMI, n1->nbinary.ch2, n2);
+			n1->nbinary.ch2 = n3;
+			n1 = n3;
+		}
+		switch (tok) {
+		case TBACKGND:
+		case TSEMI:
+			tok = readtoken();
+			/* FALLTHROUGH */
+		case TNL:
+			if (tok == TNL) {
+				parseheredoc();
+				if (nlflag)
+					return ntop;
+			} else if (tok == TEOF && nlflag) {
+				parseheredoc();
+				return ntop;
+			} else {
+				tokpushback++;
+			}
+			checkkwd = CHKNL | CHKKWD | CHKALIAS;
+			if (!nlflag && tokendlist[peektoken()])
+				return ntop;
+			break;
+		case TEOF:
+			if (heredoclist)
+				parseheredoc();
+			else
+				pungetc();		/* push back EOF on input */
+			return ntop;
+		default:
+			if (nlflag)
+				synexpect(-1);
+			tokpushback++;
+			return ntop;
+		}
+	}
+}
+
+
+
+static union node *
+andor(void)
+{
+	union node *n;
+	int t;
+
+	n = pipeline();
+	for (;;) {
+		if ((t = readtoken()) == TAND) {
+			t = NAND;
+		} else if (t == TOR) {
+			t = NOR;
+		} else {
+			tokpushback++;
+			return n;
+		}
+		n = makebinary(t, n, pipeline());
+	}
+}
+
+
+
+static union node *
+pipeline(void)
+{
+	union node *n1, *n2, *pipenode;
+	struct nodelist *lp, *prev;
+	int negate, t;
+
+	negate = 0;
+	checkkwd = CHKNL | CHKKWD | CHKALIAS;
+	TRACE(("pipeline: entered\n"));
+	while (readtoken() == TNOT)
+		negate = !negate;
+	tokpushback++;
+	n1 = command();
+	if (readtoken() == TPIPE) {
+		pipenode = (union node *)stalloc(sizeof (struct npipe));
+		pipenode->type = NPIPE;
+		pipenode->npipe.backgnd = 0;
+		lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
+		pipenode->npipe.cmdlist = lp;
+		lp->n = n1;
+		do {
+			prev = lp;
+			lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
+			checkkwd = CHKNL | CHKKWD | CHKALIAS;
+			t = readtoken();
+			tokpushback++;
+			if (t == TNOT)
+				lp->n = pipeline();
+			else
+				lp->n = command();
+			prev->next = lp;
+		} while (readtoken() == TPIPE);
+		lp->next = NULL;
+		n1 = pipenode;
+	}
+	tokpushback++;
+	if (negate) {
+		n2 = (union node *)stalloc(sizeof (struct nnot));
+		n2->type = NNOT;
+		n2->nnot.com = n1;
+		return n2;
+	} else
+		return n1;
+}
+
+
+
+static union node *
+command(void)
+{
+	union node *n1, *n2;
+	union node *ap, **app;
+	union node *cp, **cpp;
+	union node *redir, **rpp;
+	int t;
+	int is_subshell;
+
+	checkkwd = CHKNL | CHKKWD | CHKALIAS;
+	is_subshell = 0;
+	redir = NULL;
+	n1 = NULL;
+	rpp = &redir;
+
+	/* Check for redirection which may precede command */
+	while (readtoken() == TREDIR) {
+		*rpp = n2 = redirnode;
+		rpp = &n2->nfile.next;
+		parsefname();
+	}
+	tokpushback++;
+
+	switch (readtoken()) {
+	case TIF:
+		n1 = (union node *)stalloc(sizeof (struct nif));
+		n1->type = NIF;
+		if ((n1->nif.test = list(0)) == NULL)
+			synexpect(-1);
+		consumetoken(TTHEN);
+		n1->nif.ifpart = list(0);
+		n2 = n1;
+		while (readtoken() == TELIF) {
+			n2->nif.elsepart = (union node *)stalloc(sizeof (struct nif));
+			n2 = n2->nif.elsepart;
+			n2->type = NIF;
+			if ((n2->nif.test = list(0)) == NULL)
+				synexpect(-1);
+			consumetoken(TTHEN);
+			n2->nif.ifpart = list(0);
+		}
+		if (lasttoken == TELSE)
+			n2->nif.elsepart = list(0);
+		else {
+			n2->nif.elsepart = NULL;
+			tokpushback++;
+		}
+		consumetoken(TFI);
+		checkkwd = CHKKWD | CHKALIAS;
+		break;
+	case TWHILE:
+	case TUNTIL:
+		t = lasttoken;
+		if ((n1 = list(0)) == NULL)
+			synexpect(-1);
+		consumetoken(TDO);
+		n1 = makebinary((t == TWHILE)? NWHILE : NUNTIL, n1, list(0));
+		consumetoken(TDONE);
+		checkkwd = CHKKWD | CHKALIAS;
+		break;
+	case TFOR:
+		if (readtoken() != TWORD || quoteflag || ! goodname(wordtext))
+			synerror("Bad for loop variable");
+		n1 = (union node *)stalloc(sizeof (struct nfor));
+		n1->type = NFOR;
+		n1->nfor.var = wordtext;
+		while (readtoken() == TNL)
+			;
+		if (lasttoken == TWORD && ! quoteflag && equal(wordtext, "in")) {
+			app = &ap;
+			while (readtoken() == TWORD) {
+				n2 = makename();
+				*app = n2;
+				app = &n2->narg.next;
+			}
+			*app = NULL;
+			n1->nfor.args = ap;
+			if (lasttoken != TNL && lasttoken != TSEMI)
+				synexpect(-1);
+		} else {
+			static char argvars[5] = {
+				CTLVAR, VSNORMAL|VSQUOTE, '@', '=', '\0'
+			};
+			n2 = (union node *)stalloc(sizeof (struct narg));
+			n2->type = NARG;
+			n2->narg.text = argvars;
+			n2->narg.backquote = NULL;
+			n2->narg.next = NULL;
+			n1->nfor.args = n2;
+			/*
+			 * Newline or semicolon here is optional (but note
+			 * that the original Bourne shell only allowed NL).
+			 */
+			if (lasttoken != TNL && lasttoken != TSEMI)
+				tokpushback++;
+		}
+		checkkwd = CHKNL | CHKKWD | CHKALIAS;
+		if ((t = readtoken()) == TDO)
+			t = TDONE;
+		else if (t == TBEGIN)
+			t = TEND;
+		else
+			synexpect(-1);
+		n1->nfor.body = list(0);
+		consumetoken(t);
+		checkkwd = CHKKWD | CHKALIAS;
+		break;
+	case TCASE:
+		n1 = (union node *)stalloc(sizeof (struct ncase));
+		n1->type = NCASE;
+		consumetoken(TWORD);
+		n1->ncase.expr = makename();
+		while (readtoken() == TNL);
+		if (lasttoken != TWORD || ! equal(wordtext, "in"))
+			synerror("expecting \"in\"");
+		cpp = &n1->ncase.cases;
+		checkkwd = CHKNL | CHKKWD, readtoken();
+		while (lasttoken != TESAC) {
+			*cpp = cp = (union node *)stalloc(sizeof (struct nclist));
+			cp->type = NCLIST;
+			app = &cp->nclist.pattern;
+			if (lasttoken == TLP)
+				readtoken();
+			for (;;) {
+				*app = ap = makename();
+				checkkwd = CHKNL | CHKKWD;
+				if (readtoken() != TPIPE)
+					break;
+				app = &ap->narg.next;
+				readtoken();
+			}
+			ap->narg.next = NULL;
+			if (lasttoken != TRP)
+				synexpect(TRP);
+			cp->nclist.body = list(0);
+
+			checkkwd = CHKNL | CHKKWD | CHKALIAS;
+			if ((t = readtoken()) != TESAC) {
+				if (t == TENDCASE)
+					;
+				else if (t == TFALLTHRU)
+					cp->type = NCLISTFALLTHRU;
+				else
+					synexpect(TENDCASE);
+				checkkwd = CHKNL | CHKKWD, readtoken();
+			}
+			cpp = &cp->nclist.next;
+		}
+		*cpp = NULL;
+		checkkwd = CHKKWD | CHKALIAS;
+		break;
+	case TLP:
+		n1 = (union node *)stalloc(sizeof (struct nredir));
+		n1->type = NSUBSHELL;
+		n1->nredir.n = list(0);
+		n1->nredir.redirect = NULL;
+		consumetoken(TRP);
+		checkkwd = CHKKWD | CHKALIAS;
+		is_subshell = 1;
+		break;
+	case TBEGIN:
+		n1 = list(0);
+		consumetoken(TEND);
+		checkkwd = CHKKWD | CHKALIAS;
+		break;
+	/* A simple command must have at least one redirection or word. */
+	case TBACKGND:
+	case TSEMI:
+	case TAND:
+	case TOR:
+	case TPIPE:
+	case TENDCASE:
+	case TFALLTHRU:
+	case TEOF:
+	case TNL:
+	case TRP:
+		if (!redir)
+			synexpect(-1);
+	case TWORD:
+		tokpushback++;
+		n1 = simplecmd(rpp, redir);
+		return n1;
+	default:
+		synexpect(-1);
+	}
+
+	/* Now check for redirection which may follow command */
+	while (readtoken() == TREDIR) {
+		*rpp = n2 = redirnode;
+		rpp = &n2->nfile.next;
+		parsefname();
+	}
+	tokpushback++;
+	*rpp = NULL;
+	if (redir) {
+		if (!is_subshell) {
+			n2 = (union node *)stalloc(sizeof (struct nredir));
+			n2->type = NREDIR;
+			n2->nredir.n = n1;
+			n1 = n2;
+		}
+		n1->nredir.redirect = redir;
+	}
+
+	return n1;
+}
+
+
+static union node *
+simplecmd(union node **rpp, union node *redir)
+{
+	union node *args, **app;
+	union node **orig_rpp = rpp;
+	union node *n = NULL;
+	int special;
+	int savecheckkwd;
+
+	/* If we don't have any redirections already, then we must reset */
+	/* rpp to be the address of the local redir variable.  */
+	if (redir == 0)
+		rpp = &redir;
+
+	args = NULL;
+	app = &args;
+	/*
+	 * We save the incoming value, because we need this for shell
+	 * functions.  There can not be a redirect or an argument between
+	 * the function name and the open parenthesis.
+	 */
+	orig_rpp = rpp;
+
+	savecheckkwd = CHKALIAS;
+
+	for (;;) {
+		checkkwd = savecheckkwd;
+		if (readtoken() == TWORD) {
+			n = makename();
+			*app = n;
+			app = &n->narg.next;
+			if (savecheckkwd != 0 && !isassignment(wordtext))
+				savecheckkwd = 0;
+		} else if (lasttoken == TREDIR) {
+			*rpp = n = redirnode;
+			rpp = &n->nfile.next;
+			parsefname();	/* read name of redirection file */
+		} else if (lasttoken == TLP && app == &args->narg.next
+					    && rpp == orig_rpp) {
+			/* We have a function */
+			consumetoken(TRP);
+			funclinno = plinno;
+			/*
+			 * - Require plain text.
+			 * - Functions with '/' cannot be called.
+			 * - Reject name=().
+			 * - Reject ksh extended glob patterns.
+			 */
+			if (!noexpand(n->narg.text) || quoteflag ||
+			    strchr(n->narg.text, '/') ||
+			    strchr("!%*+-=?@}~",
+				n->narg.text[strlen(n->narg.text) - 1]))
+				synerror("Bad function name");
+			rmescapes(n->narg.text);
+			if (find_builtin(n->narg.text, &special) >= 0 &&
+			    special)
+				synerror("Cannot override a special builtin with a function");
+			n->type = NDEFUN;
+			n->narg.next = command();
+			funclinno = 0;
+			return n;
+		} else {
+			tokpushback++;
+			break;
+		}
+	}
+	*app = NULL;
+	*rpp = NULL;
+	n = (union node *)stalloc(sizeof (struct ncmd));
+	n->type = NCMD;
+	n->ncmd.args = args;
+	n->ncmd.redirect = redir;
+	return n;
+}
+
+static union node *
+makename(void)
+{
+	union node *n;
+
+	n = (union node *)stalloc(sizeof (struct narg));
+	n->type = NARG;
+	n->narg.next = NULL;
+	n->narg.text = wordtext;
+	n->narg.backquote = backquotelist;
+	return n;
+}
+
+static union node *
+makebinary(int type, union node *n1, union node *n2)
+{
+	union node *n;
+
+	n = (union node *)stalloc(sizeof (struct nbinary));
+	n->type = type;
+	n->nbinary.ch1 = n1;
+	n->nbinary.ch2 = n2;
+	return (n);
+}
+
+void
+forcealias(void)
+{
+	checkkwd |= CHKALIAS;
+}
+
+void
+fixredir(union node *n, const char *text, int err)
+{
+	TRACE(("Fix redir %s %d\n", text, err));
+	if (!err)
+		n->ndup.vname = NULL;
+
+	if (is_digit(text[0]) && text[1] == '\0')
+		n->ndup.dupfd = digit_val(text[0]);
+	else if (text[0] == '-' && text[1] == '\0')
+		n->ndup.dupfd = -1;
+	else {
+
+		if (err)
+			synerror("Bad fd number");
+		else
+			n->ndup.vname = makename();
+	}
+}
+
+
+static void
+parsefname(void)
+{
+	union node *n = redirnode;
+
+	consumetoken(TWORD);
+	if (n->type == NHERE) {
+		struct heredoc *here = heredoc;
+		struct heredoc *p;
+
+		if (quoteflag == 0)
+			n->type = NXHERE;
+		TRACE(("Here document %d\n", n->type));
+		if (here->striptabs) {
+			while (*wordtext == '\t')
+				wordtext++;
+		}
+		if (! noexpand(wordtext))
+			synerror("Illegal eof marker for << redirection");
+		rmescapes(wordtext);
+		here->eofmark = wordtext;
+		here->next = NULL;
+		if (heredoclist == NULL)
+			heredoclist = here;
+		else {
+			for (p = heredoclist ; p->next ; p = p->next);
+			p->next = here;
+		}
+	} else if (n->type == NTOFD || n->type == NFROMFD) {
+		fixredir(n, wordtext, 0);
+	} else {
+		n->nfile.fname = makename();
+	}
+}
+
+
+/*
+ * Input any here documents.
+ */
+
+static void
+parseheredoc(void)
+{
+	struct heredoc *here;
+	union node *n;
+
+	while (heredoclist) {
+		here = heredoclist;
+		heredoclist = here->next;
+		if (needprompt) {
+			setprompt(2);
+			needprompt = 0;
+		}
+		readtoken1(pgetc(), here->here->type == NHERE? SQSYNTAX : DQSYNTAX,
+				here->eofmark, here->striptabs);
+		n = makename();
+		here->here->nhere.doc = n;
+	}
+}
+
+static int
+peektoken(void)
+{
+	int t;
+
+	t = readtoken();
+	tokpushback++;
+	return (t);
+}
+
+static int
+readtoken(void)
+{
+	int t;
+	struct alias *ap;
+#ifdef DEBUG
+	int alreadyseen = tokpushback;
+#endif
+
+	top:
+	t = xxreadtoken();
+
+	/*
+	 * eat newlines
+	 */
+	if (checkkwd & CHKNL) {
+		while (t == TNL) {
+			parseheredoc();
+			t = xxreadtoken();
+		}
+	}
+
+	/*
+	 * check for keywords and aliases
+	 */
+	if (t == TWORD && !quoteflag)
+	{
+		const char * const *pp;
+
+		if (checkkwd & CHKKWD)
+			for (pp = parsekwd; *pp; pp++) {
+				if (**pp == *wordtext && equal(*pp, wordtext))
+				{
+					lasttoken = t = pp - parsekwd + KWDOFFSET;
+					TRACE(("keyword %s recognized\n", tokname[t]));
+					goto out;
+				}
+			}
+		if (checkkwd & CHKALIAS &&
+		    (ap = lookupalias(wordtext, 1)) != NULL) {
+			pushstring(ap->val, strlen(ap->val), ap);
+			goto top;
+		}
+	}
+out:
+	if (t != TNOT)
+		checkkwd = 0;
+
+#ifdef DEBUG
+	if (!alreadyseen)
+	    TRACE(("token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
+	else
+	    TRACE(("reread token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
+#endif
+	return (t);
+}
+
+
+/*
+ * Read the next input token.
+ * If the token is a word, we set backquotelist to the list of cmds in
+ *	backquotes.  We set quoteflag to true if any part of the word was
+ *	quoted.
+ * If the token is TREDIR, then we set redirnode to a structure containing
+ *	the redirection.
+ * In all cases, the variable startlinno is set to the number of the line
+ *	on which the token starts.
+ *
+ * [Change comment:  here documents and internal procedures]
+ * [Readtoken shouldn't have any arguments.  Perhaps we should make the
+ *  word parsing code into a separate routine.  In this case, readtoken
+ *  doesn't need to have any internal procedures, but parseword does.
+ *  We could also make parseoperator in essence the main routine, and
+ *  have parseword (readtoken1?) handle both words and redirection.]
+ */
+
+#define RETURN(token)	return lasttoken = token
+
+static int
+xxreadtoken(void)
+{
+	int c;
+
+	if (tokpushback) {
+		tokpushback = 0;
+		return lasttoken;
+	}
+	if (needprompt) {
+		setprompt(2);
+		needprompt = 0;
+	}
+	startlinno = plinno;
+	for (;;) {	/* until token or start of word found */
+		c = pgetc_macro();
+		switch (c) {
+		case ' ': case '\t':
+			continue;
+		case '#':
+			while ((c = pgetc()) != '\n' && c != PEOF);
+			pungetc();
+			continue;
+		case '\\':
+			if (pgetc() == '\n') {
+				startlinno = ++plinno;
+				if (doprompt)
+					setprompt(2);
+				else
+					setprompt(0);
+				continue;
+			}
+			pungetc();
+			/* FALLTHROUGH */
+		default:
+			return readtoken1(c, BASESYNTAX, (char *)NULL, 0);
+		case '\n':
+			plinno++;
+			needprompt = doprompt;
+			RETURN(TNL);
+		case PEOF:
+			RETURN(TEOF);
+		case '&':
+			if (pgetc_linecont() == '&')
+				RETURN(TAND);
+			pungetc();
+			RETURN(TBACKGND);
+		case '|':
+			if (pgetc_linecont() == '|')
+				RETURN(TOR);
+			pungetc();
+			RETURN(TPIPE);
+		case ';':
+			c = pgetc_linecont();
+			if (c == ';')
+				RETURN(TENDCASE);
+			else if (c == '&')
+				RETURN(TFALLTHRU);
+			pungetc();
+			RETURN(TSEMI);
+		case '(':
+			RETURN(TLP);
+		case ')':
+			RETURN(TRP);
+		}
+	}
+#undef RETURN
+}
+
+
+#define MAXNEST_static 8
+struct tokenstate
+{
+	const char *syntax; /* *SYNTAX */
+	int parenlevel; /* levels of parentheses in arithmetic */
+	enum tokenstate_category
+	{
+		TSTATE_TOP,
+		TSTATE_VAR_OLD, /* ${var+-=?}, inherits dquotes */
+		TSTATE_VAR_NEW, /* other ${var...}, own dquote state */
+		TSTATE_ARITH
+	} category;
+};
+
+
+/*
+ * Check to see whether we are at the end of the here document.  When this
+ * is called, c is set to the first character of the next input line.  If
+ * we are at the end of the here document, this routine sets the c to PEOF.
+ * The new value of c is returned.
+ */
+
+static int
+checkend(int c, const char *eofmark, int striptabs)
+{
+	if (striptabs) {
+		while (c == '\t')
+			c = pgetc();
+	}
+	if (c == *eofmark) {
+		int c2;
+		const char *q;
+
+		for (q = eofmark + 1; c2 = pgetc(), *q != '\0' && c2 == *q; q++)
+			;
+		if ((c2 == PEOF || c2 == '\n') && *q == '\0') {
+			c = PEOF;
+			if (c2 == '\n') {
+				plinno++;
+				needprompt = doprompt;
+			}
+		} else {
+			pungetc();
+			pushstring(eofmark + 1, q - (eofmark + 1), NULL);
+		}
+	}
+	return (c);
+}
+
+
+/*
+ * Parse a redirection operator.  The variable "out" points to a string
+ * specifying the fd to be redirected.  The variable "c" contains the
+ * first character of the redirection operator.
+ */
+
+static void
+parseredir(char *out, int c)
+{
+	char fd = *out;
+	union node *np;
+
+	np = (union node *)stalloc(sizeof (struct nfile));
+	if (c == '>') {
+		np->nfile.fd = 1;
+		c = pgetc_linecont();
+		if (c == '>')
+			np->type = NAPPEND;
+		else if (c == '&')
+			np->type = NTOFD;
+		else if (c == '|')
+			np->type = NCLOBBER;
+		else {
+			np->type = NTO;
+			pungetc();
+		}
+	} else {	/* c == '<' */
+		np->nfile.fd = 0;
+		c = pgetc_linecont();
+		if (c == '<') {
+			if (sizeof (struct nfile) != sizeof (struct nhere)) {
+				np = (union node *)stalloc(sizeof (struct nhere));
+				np->nfile.fd = 0;
+			}
+			np->type = NHERE;
+			heredoc = (struct heredoc *)stalloc(sizeof (struct heredoc));
+			heredoc->here = np;
+			if ((c = pgetc_linecont()) == '-') {
+				heredoc->striptabs = 1;
+			} else {
+				heredoc->striptabs = 0;
+				pungetc();
+			}
+		} else if (c == '&')
+			np->type = NFROMFD;
+		else if (c == '>')
+			np->type = NFROMTO;
+		else {
+			np->type = NFROM;
+			pungetc();
+		}
+	}
+	if (fd != '\0')
+		np->nfile.fd = digit_val(fd);
+	redirnode = np;
+}
+
+/*
+ * Called to parse command substitutions.
+ */
+
+static char *
+parsebackq(char *out, struct nodelist **pbqlist,
+		int oldstyle, int dblquote, int quoted)
+{
+	struct nodelist **nlpp;
+	union node *n;
+	char *volatile str;
+	struct jmploc jmploc;
+	struct jmploc *const savehandler = handler;
+	size_t savelen;
+	int saveprompt;
+	const int bq_startlinno = plinno;
+	char *volatile ostr = NULL;
+	struct parsefile *const savetopfile = getcurrentfile();
+	struct heredoc *const saveheredoclist = heredoclist;
+	struct heredoc *here;
+
+	str = NULL;
+	if (setjmp(jmploc.loc)) {
+		popfilesupto(savetopfile);
+		if (str)
+			ckfree(str);
+		if (ostr)
+			ckfree(ostr);
+		heredoclist = saveheredoclist;
+		handler = savehandler;
+		if (exception == EXERROR) {
+			startlinno = bq_startlinno;
+			synerror("Error in command substitution");
+		}
+		longjmp(handler->loc, 1);
+	}
+	INTOFF;
+	savelen = out - stackblock();
+	if (savelen > 0) {
+		str = ckmalloc(savelen);
+		memcpy(str, stackblock(), savelen);
+	}
+	handler = &jmploc;
+	heredoclist = NULL;
+	INTON;
+        if (oldstyle) {
+                /* We must read until the closing backquote, giving special
+                   treatment to some slashes, and then push the string and
+                   reread it as input, interpreting it normally.  */
+                char *oout;
+                int c;
+                int olen;
+
+
+                STARTSTACKSTR(oout);
+		for (;;) {
+			if (needprompt) {
+				setprompt(2);
+				needprompt = 0;
+			}
+			CHECKSTRSPACE(2, oout);
+			c = pgetc_linecont();
+			if (c == '`')
+				break;
+			switch (c) {
+			case '\\':
+				c = pgetc();
+                                if (c != '\\' && c != '`' && c != '$'
+                                    && (!dblquote || c != '"'))
+                                        USTPUTC('\\', oout);
+				break;
+
+			case '\n':
+				plinno++;
+				needprompt = doprompt;
+				break;
+
+			case PEOF:
+			        startlinno = plinno;
+				synerror("EOF in backquote substitution");
+ 				break;
+
+			default:
+				break;
+			}
+			USTPUTC(c, oout);
+                }
+                USTPUTC('\0', oout);
+                olen = oout - stackblock();
+		INTOFF;
+		ostr = ckmalloc(olen);
+		memcpy(ostr, stackblock(), olen);
+		setinputstring(ostr, 1);
+		INTON;
+        }
+	nlpp = pbqlist;
+	while (*nlpp)
+		nlpp = &(*nlpp)->next;
+	*nlpp = (struct nodelist *)stalloc(sizeof (struct nodelist));
+	(*nlpp)->next = NULL;
+
+	if (oldstyle) {
+		saveprompt = doprompt;
+		doprompt = 0;
+	}
+
+	n = list(0);
+
+	if (oldstyle) {
+		if (peektoken() != TEOF)
+			synexpect(-1);
+		doprompt = saveprompt;
+	} else
+		consumetoken(TRP);
+
+	(*nlpp)->n = n;
+        if (oldstyle) {
+		/*
+		 * Start reading from old file again, ignoring any pushed back
+		 * tokens left from the backquote parsing
+		 */
+                popfile();
+		tokpushback = 0;
+	}
+	STARTSTACKSTR(out);
+	CHECKSTRSPACE(savelen + 1, out);
+	INTOFF;
+	if (str) {
+		memcpy(out, str, savelen);
+		STADJUST(savelen, out);
+		ckfree(str);
+		str = NULL;
+	}
+	if (ostr) {
+		ckfree(ostr);
+		ostr = NULL;
+	}
+	here = saveheredoclist;
+	if (here != NULL) {
+		while (here->next != NULL)
+			here = here->next;
+		here->next = heredoclist;
+		heredoclist = saveheredoclist;
+	}
+	handler = savehandler;
+	INTON;
+	if (quoted)
+		USTPUTC(CTLBACKQ | CTLQUOTE, out);
+	else
+		USTPUTC(CTLBACKQ, out);
+	return out;
+}
+
+
+/*
+ * Called to parse a backslash escape sequence inside $'...'.
+ * The backslash has already been read.
+ */
+static char *
+readcstyleesc(char *out)
+{
+	int c, v, i, n;
+
+	c = pgetc();
+	switch (c) {
+	case '\0':
+		synerror("Unterminated quoted string");
+	case '\n':
+		plinno++;
+		if (doprompt)
+			setprompt(2);
+		else
+			setprompt(0);
+		return out;
+	case '\\':
+	case '\'':
+	case '"':
+		v = c;
+		break;
+	case 'a': v = '\a'; break;
+	case 'b': v = '\b'; break;
+	case 'e': v = '\033'; break;
+	case 'f': v = '\f'; break;
+	case 'n': v = '\n'; break;
+	case 'r': v = '\r'; break;
+	case 't': v = '\t'; break;
+	case 'v': v = '\v'; break;
+	case 'x':
+		  v = 0;
+		  for (;;) {
+			  c = pgetc();
+			  if (c >= '0' && c <= '9')
+				  v = (v << 4) + c - '0';
+			  else if (c >= 'A' && c <= 'F')
+				  v = (v << 4) + c - 'A' + 10;
+			  else if (c >= 'a' && c <= 'f')
+				  v = (v << 4) + c - 'a' + 10;
+			  else
+				  break;
+		  }
+		  pungetc();
+		  break;
+	case '0': case '1': case '2': case '3':
+	case '4': case '5': case '6': case '7':
+		  v = c - '0';
+		  c = pgetc();
+		  if (c >= '0' && c <= '7') {
+			  v <<= 3;
+			  v += c - '0';
+			  c = pgetc();
+			  if (c >= '0' && c <= '7') {
+				  v <<= 3;
+				  v += c - '0';
+			  } else
+				  pungetc();
+		  } else
+			  pungetc();
+		  break;
+	case 'c':
+		  c = pgetc();
+		  if (c < 0x3f || c > 0x7a || c == 0x60)
+			  synerror("Bad escape sequence");
+		  if (c == '\\' && pgetc() != '\\')
+			  synerror("Bad escape sequence");
+		  if (c == '?')
+			  v = 127;
+		  else
+			  v = c & 0x1f;
+		  break;
+	case 'u':
+	case 'U':
+		  n = c == 'U' ? 8 : 4;
+		  v = 0;
+		  for (i = 0; i < n; i++) {
+			  c = pgetc();
+			  if (c >= '0' && c <= '9')
+				  v = (v << 4) + c - '0';
+			  else if (c >= 'A' && c <= 'F')
+				  v = (v << 4) + c - 'A' + 10;
+			  else if (c >= 'a' && c <= 'f')
+				  v = (v << 4) + c - 'a' + 10;
+			  else
+				  synerror("Bad escape sequence");
+		  }
+		  if (v == 0 || (v >= 0xd800 && v <= 0xdfff))
+			  synerror("Bad escape sequence");
+		  /* We really need iconv here. */
+		  if (initial_localeisutf8 && v > 127) {
+			  CHECKSTRSPACE(4, out);
+			  /*
+			   * We cannot use wctomb() as the locale may have
+			   * changed.
+			   */
+			  if (v <= 0x7ff) {
+				  USTPUTC(0xc0 | v >> 6, out);
+				  USTPUTC(0x80 | (v & 0x3f), out);
+				  return out;
+			  } else if (v <= 0xffff) {
+				  USTPUTC(0xe0 | v >> 12, out);
+				  USTPUTC(0x80 | ((v >> 6) & 0x3f), out);
+				  USTPUTC(0x80 | (v & 0x3f), out);
+				  return out;
+			  } else if (v <= 0x10ffff) {
+				  USTPUTC(0xf0 | v >> 18, out);
+				  USTPUTC(0x80 | ((v >> 12) & 0x3f), out);
+				  USTPUTC(0x80 | ((v >> 6) & 0x3f), out);
+				  USTPUTC(0x80 | (v & 0x3f), out);
+				  return out;
+			  }
+		  }
+		  if (v > 127)
+			  v = '?';
+		  break;
+	default:
+		  synerror("Bad escape sequence");
+	}
+	v = (char)v;
+	/*
+	 * We can't handle NUL bytes.
+	 * POSIX says we should skip till the closing quote.
+	 */
+	if (v == '\0') {
+		while ((c = pgetc()) != '\'') {
+			if (c == '\\')
+				c = pgetc();
+			if (c == PEOF)
+				synerror("Unterminated quoted string");
+			if (c == '\n') {
+				plinno++;
+				if (doprompt)
+					setprompt(2);
+				else
+					setprompt(0);
+			}
+		}
+		pungetc();
+		return out;
+	}
+	if (SQSYNTAX[v] == CCTL)
+		USTPUTC(CTLESC, out);
+	USTPUTC(v, out);
+	return out;
+}
+
+
+/*
+ * If eofmark is NULL, read a word or a redirection symbol.  If eofmark
+ * is not NULL, read a here document.  In the latter case, eofmark is the
+ * word which marks the end of the document and striptabs is true if
+ * leading tabs should be stripped from the document.  The argument firstc
+ * is the first character of the input token or document.
+ *
+ * Because C does not have internal subroutines, I have simulated them
+ * using goto's to implement the subroutine linkage.  The following macros
+ * will run code that appears at the end of readtoken1.
+ */
+
+#define PARSESUB()	{goto parsesub; parsesub_return:;}
+#define	PARSEARITH()	{goto parsearith; parsearith_return:;}
+
+static int
+readtoken1(int firstc, char const *initialsyntax, const char *eofmark,
+    int striptabs)
+{
+	int c = firstc;
+	char *out;
+	int len;
+	struct nodelist *bqlist;
+	int quotef;
+	int newvarnest;
+	int level;
+	int synentry;
+	struct tokenstate state_static[MAXNEST_static];
+	int maxnest = MAXNEST_static;
+	struct tokenstate *state = state_static;
+	int sqiscstyle = 0;
+
+	startlinno = plinno;
+	quotef = 0;
+	bqlist = NULL;
+	newvarnest = 0;
+	level = 0;
+	state[level].syntax = initialsyntax;
+	state[level].parenlevel = 0;
+	state[level].category = TSTATE_TOP;
+
+	STARTSTACKSTR(out);
+	loop: {	/* for each line, until end of word */
+		if (eofmark)
+			/* set c to PEOF if at end of here document */
+			c = checkend(c, eofmark, striptabs);
+		for (;;) {	/* until end of line or end of word */
+			CHECKSTRSPACE(4, out);	/* permit 4 calls to USTPUTC */
+
+			synentry = state[level].syntax[c];
+
+			switch(synentry) {
+			case CNL:	/* '\n' */
+				if (state[level].syntax == BASESYNTAX)
+					goto endword;	/* exit outer loop */
+				USTPUTC(c, out);
+				plinno++;
+				if (doprompt)
+					setprompt(2);
+				else
+					setprompt(0);
+				c = pgetc();
+				goto loop;		/* continue outer loop */
+			case CSBACK:
+				if (sqiscstyle) {
+					out = readcstyleesc(out);
+					break;
+				}
+				/* FALLTHROUGH */
+			case CWORD:
+				USTPUTC(c, out);
+				break;
+			case CCTL:
+				if (eofmark == NULL || initialsyntax != SQSYNTAX)
+					USTPUTC(CTLESC, out);
+				USTPUTC(c, out);
+				break;
+			case CBACK:	/* backslash */
+				c = pgetc();
+				if (c == PEOF) {
+					USTPUTC('\\', out);
+					pungetc();
+				} else if (c == '\n') {
+					plinno++;
+					if (doprompt)
+						setprompt(2);
+					else
+						setprompt(0);
+				} else {
+					if (state[level].syntax == DQSYNTAX &&
+					    c != '\\' && c != '`' && c != '$' &&
+					    (c != '"' || (eofmark != NULL &&
+						newvarnest == 0)) &&
+					    (c != '}' || state[level].category != TSTATE_VAR_OLD))
+						USTPUTC('\\', out);
+					if ((eofmark == NULL ||
+					    newvarnest > 0) &&
+					    state[level].syntax == BASESYNTAX)
+						USTPUTC(CTLQUOTEMARK, out);
+					if (SQSYNTAX[c] == CCTL)
+						USTPUTC(CTLESC, out);
+					USTPUTC(c, out);
+					if ((eofmark == NULL ||
+					    newvarnest > 0) &&
+					    state[level].syntax == BASESYNTAX &&
+					    state[level].category == TSTATE_VAR_OLD)
+						USTPUTC(CTLQUOTEEND, out);
+					quotef++;
+				}
+				break;
+			case CSQUOTE:
+				USTPUTC(CTLQUOTEMARK, out);
+				state[level].syntax = SQSYNTAX;
+				sqiscstyle = 0;
+				break;
+			case CDQUOTE:
+				USTPUTC(CTLQUOTEMARK, out);
+				state[level].syntax = DQSYNTAX;
+				break;
+			case CENDQUOTE:
+				if (eofmark != NULL && newvarnest == 0)
+					USTPUTC(c, out);
+				else {
+					if (state[level].category == TSTATE_VAR_OLD)
+						USTPUTC(CTLQUOTEEND, out);
+					state[level].syntax = BASESYNTAX;
+					quotef++;
+				}
+				break;
+			case CVAR:	/* '$' */
+				PARSESUB();		/* parse substitution */
+				break;
+			case CENDVAR:	/* '}' */
+				if (level > 0 &&
+				    ((state[level].category == TSTATE_VAR_OLD &&
+				      state[level].syntax ==
+				      state[level - 1].syntax) ||
+				    (state[level].category == TSTATE_VAR_NEW &&
+				     state[level].syntax == BASESYNTAX))) {
+					if (state[level].category == TSTATE_VAR_NEW)
+						newvarnest--;
+					level--;
+					USTPUTC(CTLENDVAR, out);
+				} else {
+					USTPUTC(c, out);
+				}
+				break;
+			case CLP:	/* '(' in arithmetic */
+				state[level].parenlevel++;
+				USTPUTC(c, out);
+				break;
+			case CRP:	/* ')' in arithmetic */
+				if (state[level].parenlevel > 0) {
+					USTPUTC(c, out);
+					--state[level].parenlevel;
+				} else {
+					if (pgetc_linecont() == ')') {
+						if (level > 0 &&
+						    state[level].category == TSTATE_ARITH) {
+							level--;
+							USTPUTC(CTLENDARI, out);
+						} else
+							USTPUTC(')', out);
+					} else {
+						/*
+						 * unbalanced parens
+						 *  (don't 2nd guess - no error)
+						 */
+						pungetc();
+						USTPUTC(')', out);
+					}
+				}
+				break;
+			case CBQUOTE:	/* '`' */
+				out = parsebackq(out, &bqlist, 1,
+				    state[level].syntax == DQSYNTAX &&
+				    (eofmark == NULL || newvarnest > 0),
+				    state[level].syntax == DQSYNTAX || state[level].syntax == ARISYNTAX);
+				break;
+			case CEOF:
+				goto endword;		/* exit outer loop */
+			case CIGN:
+				break;
+			default:
+				if (level == 0)
+					goto endword;	/* exit outer loop */
+				USTPUTC(c, out);
+			}
+			c = pgetc_macro();
+		}
+	}
+endword:
+	if (state[level].syntax == ARISYNTAX)
+		synerror("Missing '))'");
+	if (state[level].syntax != BASESYNTAX && eofmark == NULL)
+		synerror("Unterminated quoted string");
+	if (state[level].category == TSTATE_VAR_OLD ||
+	    state[level].category == TSTATE_VAR_NEW) {
+		startlinno = plinno;
+		synerror("Missing '}'");
+	}
+	if (state != state_static)
+		parser_temp_free_upto(state);
+	USTPUTC('\0', out);
+	len = out - stackblock();
+	out = stackblock();
+	if (eofmark == NULL) {
+		if ((c == '>' || c == '<')
+		 && quotef == 0
+		 && len <= 2
+		 && (*out == '\0' || is_digit(*out))) {
+			parseredir(out, c);
+			return lasttoken = TREDIR;
+		} else {
+			pungetc();
+		}
+	}
+	quoteflag = quotef;
+	backquotelist = bqlist;
+	grabstackblock(len);
+	wordtext = out;
+	return lasttoken = TWORD;
+/* end of readtoken routine */
+
+
+/*
+ * Parse a substitution.  At this point, we have read the dollar sign
+ * and nothing else.
+ */
+
+parsesub: {
+	char buf[10];
+	int subtype;
+	int typeloc;
+	int flags;
+	char *p;
+	static const char types[] = "}-+?=";
+	int bracketed_name = 0; /* used to handle ${[0-9]*} variables */
+	int linno;
+	int length;
+	int c1;
+
+	c = pgetc_linecont();
+	if (c == '(') {	/* $(command) or $((arith)) */
+		if (pgetc_linecont() == '(') {
+			PARSEARITH();
+		} else {
+			pungetc();
+			out = parsebackq(out, &bqlist, 0,
+			    state[level].syntax == DQSYNTAX &&
+			    (eofmark == NULL || newvarnest > 0),
+			    state[level].syntax == DQSYNTAX ||
+			    state[level].syntax == ARISYNTAX);
+		}
+	} else if (c == '{' || is_name(c) || is_special(c)) {
+		USTPUTC(CTLVAR, out);
+		typeloc = out - stackblock();
+		USTPUTC(VSNORMAL, out);
+		subtype = VSNORMAL;
+		flags = 0;
+		if (c == '{') {
+			bracketed_name = 1;
+			c = pgetc_linecont();
+			subtype = 0;
+		}
+varname:
+		if (!is_eof(c) && is_name(c)) {
+			length = 0;
+			do {
+				STPUTC(c, out);
+				c = pgetc_linecont();
+				length++;
+			} while (!is_eof(c) && is_in_name(c));
+			if (length == 6 &&
+			    strncmp(out - length, "LINENO", length) == 0) {
+				/* Replace the variable name with the
+				 * current line number. */
+				linno = plinno;
+				if (funclinno != 0)
+					linno -= funclinno - 1;
+				snprintf(buf, sizeof(buf), "%d", linno);
+				STADJUST(-6, out);
+				STPUTS(buf, out);
+				flags |= VSLINENO;
+			}
+		} else if (is_digit(c)) {
+			if (bracketed_name) {
+				do {
+					STPUTC(c, out);
+					c = pgetc_linecont();
+				} while (is_digit(c));
+			} else {
+				STPUTC(c, out);
+				c = pgetc_linecont();
+			}
+		} else if (is_special(c)) {
+			c1 = c;
+			c = pgetc_linecont();
+			if (subtype == 0 && c1 == '#') {
+				subtype = VSLENGTH;
+				if (strchr(types, c) == NULL && c != ':' &&
+				    c != '#' && c != '%')
+					goto varname;
+				c1 = c;
+				c = pgetc_linecont();
+				if (c1 != '}' && c == '}') {
+					pungetc();
+					c = c1;
+					goto varname;
+				}
+				pungetc();
+				c = c1;
+				c1 = '#';
+				subtype = 0;
+			}
+			USTPUTC(c1, out);
+		} else {
+			subtype = VSERROR;
+			if (c == '}')
+				pungetc();
+			else if (c == '\n' || c == PEOF)
+				synerror("Unexpected end of line in substitution");
+			else
+				USTPUTC(c, out);
+		}
+		if (subtype == 0) {
+			switch (c) {
+			case ':':
+				flags |= VSNUL;
+				c = pgetc_linecont();
+				/*FALLTHROUGH*/
+			default:
+				p = strchr(types, c);
+				if (p == NULL) {
+					if (c == '\n' || c == PEOF)
+						synerror("Unexpected end of line in substitution");
+					if (flags == VSNUL)
+						STPUTC(':', out);
+					STPUTC(c, out);
+					subtype = VSERROR;
+				} else
+					subtype = p - types + VSNORMAL;
+				break;
+			case '%':
+			case '#':
+				{
+					int cc = c;
+					subtype = c == '#' ? VSTRIMLEFT :
+							     VSTRIMRIGHT;
+					c = pgetc_linecont();
+					if (c == cc)
+						subtype++;
+					else
+						pungetc();
+					break;
+				}
+			}
+		} else if (subtype != VSERROR) {
+			if (subtype == VSLENGTH && c != '}')
+				subtype = VSERROR;
+			pungetc();
+		}
+		STPUTC('=', out);
+		if (state[level].syntax == DQSYNTAX ||
+		    state[level].syntax == ARISYNTAX)
+			flags |= VSQUOTE;
+		*(stackblock() + typeloc) = subtype | flags;
+		if (subtype != VSNORMAL) {
+			if (level + 1 >= maxnest) {
+				maxnest *= 2;
+				if (state == state_static) {
+					state = parser_temp_alloc(
+					    maxnest * sizeof(*state));
+					memcpy(state, state_static,
+					    MAXNEST_static * sizeof(*state));
+				} else
+					state = parser_temp_realloc(state,
+					    maxnest * sizeof(*state));
+			}
+			level++;
+			state[level].parenlevel = 0;
+			if (subtype == VSMINUS || subtype == VSPLUS ||
+			    subtype == VSQUESTION || subtype == VSASSIGN) {
+				/*
+				 * For operators that were in the Bourne shell,
+				 * inherit the double-quote state.
+				 */
+				state[level].syntax = state[level - 1].syntax;
+				state[level].category = TSTATE_VAR_OLD;
+			} else {
+				/*
+				 * The other operators take a pattern,
+				 * so go to BASESYNTAX.
+				 * Also, ' and " are now special, even
+				 * in here documents.
+				 */
+				state[level].syntax = BASESYNTAX;
+				state[level].category = TSTATE_VAR_NEW;
+				newvarnest++;
+			}
+		}
+	} else if (c == '\'' && state[level].syntax == BASESYNTAX) {
+		/* $'cstylequotes' */
+		USTPUTC(CTLQUOTEMARK, out);
+		state[level].syntax = SQSYNTAX;
+		sqiscstyle = 1;
+	} else {
+		USTPUTC('$', out);
+		pungetc();
+	}
+	goto parsesub_return;
+}
+
+
+/*
+ * Parse an arithmetic expansion (indicate start of one and set state)
+ */
+parsearith: {
+
+	if (level + 1 >= maxnest) {
+		maxnest *= 2;
+		if (state == state_static) {
+			state = parser_temp_alloc(
+			    maxnest * sizeof(*state));
+			memcpy(state, state_static,
+			    MAXNEST_static * sizeof(*state));
+		} else
+			state = parser_temp_realloc(state,
+			    maxnest * sizeof(*state));
+	}
+	level++;
+	state[level].syntax = ARISYNTAX;
+	state[level].parenlevel = 0;
+	state[level].category = TSTATE_ARITH;
+	USTPUTC(CTLARI, out);
+	if (state[level - 1].syntax == DQSYNTAX)
+		USTPUTC('"',out);
+	else
+		USTPUTC(' ',out);
+	goto parsearith_return;
+}
+
+} /* end of readtoken */
+
+
+/*
+ * Returns true if the text contains nothing to expand (no dollar signs
+ * or backquotes).
+ */
+
+static int
+noexpand(char *text)
+{
+	char *p;
+	char c;
+
+	p = text;
+	while ((c = *p++) != '\0') {
+		if ( c == CTLQUOTEMARK)
+			continue;
+		if (c == CTLESC)
+			p++;
+		else if (BASESYNTAX[(int)c] == CCTL)
+			return 0;
+	}
+	return 1;
+}
+
+
+/*
+ * Return true if the argument is a legal variable name (a letter or
+ * underscore followed by zero or more letters, underscores, and digits).
+ */
+
+int
+goodname(const char *name)
+{
+	const char *p;
+
+	p = name;
+	if (! is_name(*p))
+		return 0;
+	while (*++p) {
+		if (! is_in_name(*p))
+			return 0;
+	}
+	return 1;
+}
+
+
+int
+isassignment(const char *p)
+{
+	if (!is_name(*p))
+		return 0;
+	p++;
+	for (;;) {
+		if (*p == '=')
+			return 1;
+		else if (!is_in_name(*p))
+			return 0;
+		p++;
+	}
+}
+
+
+static void
+consumetoken(int token)
+{
+	if (readtoken() != token)
+		synexpect(token);
+}
+
+
+/*
+ * Called when an unexpected token is read during the parse.  The argument
+ * is the token that is expected, or -1 if more than one type of token can
+ * occur at this point.
+ */
+
+static void
+synexpect(int token)
+{
+	char msg[64];
+
+	if (token >= 0) {
+		fmtstr(msg, 64, "%s unexpected (expecting %s)",
+			tokname[lasttoken], tokname[token]);
+	} else {
+		fmtstr(msg, 64, "%s unexpected", tokname[lasttoken]);
+	}
+	synerror(msg);
+}
+
+
+static void
+synerror(const char *msg)
+{
+	if (commandname)
+		outfmt(out2, "%s: %d: ", commandname, startlinno);
+	else if (arg0)
+		outfmt(out2, "%s: ", arg0);
+	outfmt(out2, "Syntax error: %s\n", msg);
+	error((char *)NULL);
+}
+
+static void
+setprompt(int which)
+{
+	whichprompt = which;
+
+#ifndef NO_HISTORY
+	if (!el)
+#endif
+	{
+		out2str(getprompt(NULL));
+		flushout(out2);
+	}
+}
+
+static int
+pgetc_linecont(void)
+{
+	int c;
+
+	while ((c = pgetc_macro()) == '\\') {
+		c = pgetc();
+		if (c == '\n') {
+			plinno++;
+			if (doprompt)
+				setprompt(2);
+			else
+				setprompt(0);
+		} else {
+			pungetc();
+			/* Allow the backslash to be pushed back. */
+			pushstring("\\", 1, NULL);
+			return (pgetc());
+		}
+	}
+	return (c);
+}
+
+/*
+ * called by editline -- any expansions to the prompt
+ *    should be added here.
+ */
+char *
+getprompt(void *unused __unused)
+{
+	static char ps[PROMPTLEN];
+	const char *fmt;
+	const char *pwd;
+	int i, trim;
+	static char internal_error[] = "??";
+
+	/*
+	 * Select prompt format.
+	 */
+	switch (whichprompt) {
+	case 0:
+		fmt = "";
+		break;
+	case 1:
+		fmt = ps1val();
+		break;
+	case 2:
+		fmt = ps2val();
+		break;
+	default:
+		return internal_error;
+	}
+
+	/*
+	 * Format prompt string.
+	 */
+	for (i = 0; (i < 127) && (*fmt != '\0'); i++, fmt++)
+		if (*fmt == '\\')
+			switch (*++fmt) {
+
+				/*
+				 * Hostname.
+				 *
+				 * \h specifies just the local hostname,
+				 * \H specifies fully-qualified hostname.
+				 */
+			case 'h':
+			case 'H':
+				ps[i] = '\0';
+				gethostname(&ps[i], PROMPTLEN - i);
+				/* Skip to end of hostname. */
+				trim = (*fmt == 'h') ? '.' : '\0';
+				while ((ps[i+1] != '\0') && (ps[i+1] != trim))
+					i++;
+				break;
+
+				/*
+				 * Working directory.
+				 *
+				 * \W specifies just the final component,
+				 * \w specifies the entire path.
+				 */
+			case 'W':
+			case 'w':
+				pwd = lookupvar("PWD");
+				if (pwd == NULL)
+					pwd = "?";
+				if (*fmt == 'W' &&
+				    *pwd == '/' && pwd[1] != '\0')
+					strlcpy(&ps[i], strrchr(pwd, '/') + 1,
+					    PROMPTLEN - i);
+				else
+					strlcpy(&ps[i], pwd, PROMPTLEN - i);
+				/* Skip to end of path. */
+				while (ps[i + 1] != '\0')
+					i++;
+				break;
+
+				/*
+				 * Superuser status.
+				 *
+				 * '$' for normal users, '#' for root.
+				 */
+			case '$':
+				ps[i] = (geteuid() != 0) ? '$' : '#';
+				break;
+
+				/*
+				 * A literal \.
+				 */
+			case '\\':
+				ps[i] = '\\';
+				break;
+
+				/*
+				 * Emit unrecognized formats verbatim.
+				 */
+			default:
+				ps[i++] = '\\';
+				ps[i] = *fmt;
+				break;
+			}
+		else
+			ps[i] = *fmt;
+	ps[i] = '\0';
+	return (ps);
+}
+
+
+const char *
+expandstr(const char *ps)
+{
+	union node n;
+	struct jmploc jmploc;
+	struct jmploc *const savehandler = handler;
+	const int saveprompt = doprompt;
+	struct parsefile *const savetopfile = getcurrentfile();
+	struct parser_temp *const saveparser_temp = parser_temp;
+	const char *result = NULL;
+
+	if (!setjmp(jmploc.loc)) {
+		handler = &jmploc;
+		parser_temp = NULL;
+		setinputstring(ps, 1);
+		doprompt = 0;
+		readtoken1(pgetc(), DQSYNTAX, "", 0);
+		if (backquotelist != NULL)
+			error("Command substitution not allowed here");
+
+		n.narg.type = NARG;
+		n.narg.next = NULL;
+		n.narg.text = wordtext;
+		n.narg.backquote = backquotelist;
+
+		expandarg(&n, NULL, 0);
+		result = stackblock();
+		INTOFF;
+	}
+	handler = savehandler;
+	doprompt = saveprompt;
+	popfilesupto(savetopfile);
+	if (parser_temp != saveparser_temp) {
+		parser_temp_free_all();
+		parser_temp = saveparser_temp;
+	}
+	if (result != NULL) {
+		INTON;
+	} else if (exception == EXINT)
+		raise(SIGINT);
+	return result;
+}
diff --git a/external/sh/parser.h b/external/sh/parser.h
new file mode 100644
index 00000000..241de010
--- /dev/null
+++ b/external/sh/parser.h
@@ -0,0 +1,84 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)parser.h	8.3 (Berkeley) 5/4/95
+ * $FreeBSD: head/bin/sh/parser.h 261192 2014-01-26 21:19:33Z jilles $
+ */
+
+/* control characters in argument strings */
+#define CTLESC '\300'
+#define CTLVAR '\301'
+#define CTLENDVAR '\371'
+#define CTLBACKQ '\372'
+#define CTLQUOTE 01		/* ored with CTLBACKQ code if in quotes */
+/*	CTLBACKQ | CTLQUOTE == '\373' */
+#define	CTLARI	'\374'
+#define	CTLENDARI '\375'
+#define	CTLQUOTEMARK '\376'
+#define	CTLQUOTEEND '\377' /* only for ${v+-...} */
+
+/* variable substitution byte (follows CTLVAR) */
+#define VSTYPE		0x0f	/* type of variable substitution */
+#define VSNUL		0x10	/* colon--treat the empty string as unset */
+#define VSLINENO	0x20	/* expansion of $LINENO, the line number \
+				   follows immediately */
+#define VSQUOTE		0x80	/* inside double quotes--suppress splitting */
+
+/* values of VSTYPE field */
+#define VSNORMAL	0x1		/* normal variable:  $var or ${var} */
+#define VSMINUS		0x2		/* ${var-text} */
+#define VSPLUS		0x3		/* ${var+text} */
+#define VSQUESTION	0x4		/* ${var?message} */
+#define VSASSIGN	0x5		/* ${var=text} */
+#define VSTRIMLEFT	0x6		/* ${var#pattern} */
+#define VSTRIMLEFTMAX	0x7		/* ${var##pattern} */
+#define VSTRIMRIGHT	0x8		/* ${var%pattern} */
+#define VSTRIMRIGHTMAX 	0x9		/* ${var%%pattern} */
+#define VSLENGTH	0xa		/* ${#var} */
+#define VSERROR		0xb		/* Syntax error, issue when expanded */
+
+
+/*
+ * NEOF is returned by parsecmd when it encounters an end of file.  It
+ * must be distinct from NULL.
+ */
+#define NEOF ((union node *)-1)
+extern int whichprompt;		/* 1 == PS1, 2 == PS2 */
+extern const char *const parsekwd[];
+
+
+union node *parsecmd(int);
+void forcealias(void);
+void fixredir(union node *, const char *, int);
+int goodname(const char *);
+int isassignment(const char *);
+char *getprompt(void *);
+const char *expandstr(const char *);
diff --git a/external/sh/printf.c b/external/sh/printf.c
new file mode 100644
index 00000000..438b85ec
--- /dev/null
+++ b/external/sh/printf.c
@@ -0,0 +1,686 @@
+/*-
+ * Copyright 2014 Garrett D'Amore <garrett@damore.org>
+ * Copyright 2010 Nexenta Systems, Inc.  All rights reserved.
+ * Copyright (c) 1989, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+/*
+ * Important: This file is used both as a standalone program /usr/bin/printf
+ * and as a builtin for /bin/sh (#define SHELL).
+ */
+
+#ifndef SHELL
+#ifndef lint
+static char const copyright[] =
+"@(#) Copyright (c) 1989, 1993\n\
+	The Regents of the University of California.  All rights reserved.\n";
+#endif /* not lint */
+#endif
+
+#ifndef lint
+#if 0
+static char const sccsid[] = "@(#)printf.c	8.1 (Berkeley) 7/20/93";
+#endif
+static const char rcsid[] =
+  "$FreeBSD: head/usr.bin/printf/printf.c 279503 2015-03-01 21:46:55Z jilles $";
+#endif /* not lint */
+
+#include <sys/types.h>
+
+#include <ctype.h>
+#include <err.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <limits.h>
+#include <locale.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <wchar.h>
+
+#ifdef SHELL
+#define	main printfcmd
+#include "bltin/bltin.h"
+#include "options.h"
+#endif
+
+#define	PF(f, func) do {						\
+	char *b = NULL;							\
+	if (havewidth)							\
+		if (haveprec)						\
+			(void)asprintf(&b, f, fieldwidth, precision, func); \
+		else							\
+			(void)asprintf(&b, f, fieldwidth, func);	\
+	else if (haveprec)						\
+		(void)asprintf(&b, f, precision, func);			\
+	else								\
+		(void)asprintf(&b, f, func);				\
+	if (b) {							\
+		(void)fputs(b, stdout);					\
+		free(b);						\
+	}								\
+} while (0)
+
+static int	 asciicode(void);
+static char	*printf_doformat(char *, int *);
+static int	 escape(char *, int, size_t *);
+static int	 getchr(void);
+static int	 getfloating(long double *, int);
+static int	 getint(int *);
+static int	 getnum(intmax_t *, uintmax_t *, int);
+static const char
+		*getstr(void);
+static char	*mknum(char *, char);
+static void	 usage(void);
+
+static const char digits[] = "0123456789";
+
+static char end_fmt[1];
+
+static int  myargc;
+static char **myargv;
+static char **gargv;
+static char **maxargv;
+
+int
+main(int argc, char *argv[])
+{
+	size_t len;
+	int end, rval;
+	char *format, *fmt, *start;
+#ifndef SHELL
+	int ch;
+
+	(void) setlocale(LC_ALL, "");
+#endif
+
+#ifdef SHELL
+	nextopt("");
+	argc -= argptr - argv;
+	argv = argptr;
+#else
+	while ((ch = getopt(argc, argv, "")) != -1)
+		switch (ch) {
+		case '?':
+		default:
+			usage();
+			return (1);
+		}
+	argc -= optind;
+	argv += optind;
+#endif
+
+	if (argc < 1) {
+		usage();
+		return (1);
+	}
+
+#ifdef SHELL
+	INTOFF;
+#endif
+	/*
+	 * Basic algorithm is to scan the format string for conversion
+	 * specifications -- once one is found, find out if the field
+	 * width or precision is a '*'; if it is, gather up value.  Note,
+	 * format strings are reused as necessary to use up the provided
+	 * arguments, arguments of zero/null string are provided to use
+	 * up the format string.
+	 */
+	fmt = format = *argv;
+	escape(fmt, 1, &len);		/* backslash interpretation */
+	rval = end = 0;
+	gargv = ++argv;
+
+	for (;;) {
+		maxargv = gargv;
+
+		myargv = gargv;
+		for (myargc = 0; gargv[myargc]; myargc++)
+			/* nop */;
+		start = fmt;
+		while (fmt < format + len) {
+			if (fmt[0] == '%') {
+				fwrite(start, 1, fmt - start, stdout);
+				if (fmt[1] == '%') {
+					/* %% prints a % */
+					putchar('%');
+					fmt += 2;
+				} else {
+					fmt = printf_doformat(fmt, &rval);
+					if (fmt == NULL || fmt == end_fmt) {
+#ifdef SHELL
+						INTON;
+#endif
+						return (fmt == NULL ? 1 : rval);
+					}
+					end = 0;
+				}
+				start = fmt;
+			} else
+				fmt++;
+			if (gargv > maxargv)
+				maxargv = gargv;
+		}
+		gargv = maxargv;
+
+		if (end == 1) {
+			warnx("missing format character");
+#ifdef SHELL
+			INTON;
+#endif
+			return (1);
+		}
+		fwrite(start, 1, fmt - start, stdout);
+		if (!*gargv) {
+#ifdef SHELL
+			INTON;
+#endif
+			return (rval);
+		}
+		/* Restart at the beginning of the format string. */
+		fmt = format;
+		end = 1;
+	}
+	/* NOTREACHED */
+}
+
+
+static char *
+printf_doformat(char *fmt, int *rval)
+{
+	static const char skip1[] = "#'-+ 0";
+	int fieldwidth, haveprec, havewidth, mod_ldbl, precision;
+	char convch, nextch;
+	char start[strlen(fmt) + 1];
+	char **fargv;
+	char *dptr;
+	int l;
+
+	dptr = start;
+	*dptr++ = '%';
+	*dptr = 0;
+
+	fmt++;
+
+	/* look for "n$" field index specifier */
+	l = strspn(fmt, digits);
+	if ((l > 0) && (fmt[l] == '$')) {
+		int idx = atoi(fmt);
+		if (idx <= myargc) {
+			gargv = &myargv[idx - 1];
+		} else {
+			gargv = &myargv[myargc];
+		}
+		if (gargv > maxargv)
+			maxargv = gargv;
+		fmt += l + 1;
+
+		/* save format argument */
+		fargv = gargv;
+	} else {
+		fargv = NULL;
+	}
+
+	/* skip to field width */
+	while (*fmt && strchr(skip1, *fmt) != NULL) {
+		*dptr++ = *fmt++;
+		*dptr = 0;
+	}
+
+	if (*fmt == '*') {
+
+		fmt++;
+		l = strspn(fmt, digits);
+		if ((l > 0) && (fmt[l] == '$')) {
+			int idx = atoi(fmt);
+			if (fargv == NULL) {
+				warnx("incomplete use of n$");
+				return (NULL);
+			}
+			if (idx <= myargc) {
+				gargv = &myargv[idx - 1];
+			} else {
+				gargv = &myargv[myargc];
+			}
+			fmt += l + 1;
+		} else if (fargv != NULL) {
+			warnx("incomplete use of n$");
+			return (NULL);
+		}
+
+		if (getint(&fieldwidth))
+			return (NULL);
+		if (gargv > maxargv)
+			maxargv = gargv;
+		havewidth = 1;
+
+		*dptr++ = '*';
+		*dptr = 0;
+	} else {
+		havewidth = 0;
+
+		/* skip to possible '.', get following precision */
+		while (isdigit(*fmt)) {
+			*dptr++ = *fmt++;
+			*dptr = 0;
+		}
+	}
+
+	if (*fmt == '.') {
+		/* precision present? */
+		fmt++;
+		*dptr++ = '.';
+
+		if (*fmt == '*') {
+
+			fmt++;
+			l = strspn(fmt, digits);
+			if ((l > 0) && (fmt[l] == '$')) {
+				int idx = atoi(fmt);
+				if (fargv == NULL) {
+					warnx("incomplete use of n$");
+					return (NULL);
+				}
+				if (idx <= myargc) {
+					gargv = &myargv[idx - 1];
+				} else {
+					gargv = &myargv[myargc];
+				}
+				fmt += l + 1;
+			} else if (fargv != NULL) {
+				warnx("incomplete use of n$");
+				return (NULL);
+			}
+
+			if (getint(&precision))
+				return (NULL);
+			if (gargv > maxargv)
+				maxargv = gargv;
+			haveprec = 1;
+			*dptr++ = '*';
+			*dptr = 0;
+		} else {
+			haveprec = 0;
+
+			/* skip to conversion char */
+			while (isdigit(*fmt)) {
+				*dptr++ = *fmt++;
+				*dptr = 0;
+			}
+		}
+	} else
+		haveprec = 0;
+	if (!*fmt) {
+		warnx("missing format character");
+		return (NULL);
+	}
+	*dptr++ = *fmt;
+	*dptr = 0;
+
+	/*
+	 * Look for a length modifier.  POSIX doesn't have these, so
+	 * we only support them for floating-point conversions, which
+	 * are extensions.  This is useful because the L modifier can
+	 * be used to gain extra range and precision, while omitting
+	 * it is more likely to produce consistent results on different
+	 * architectures.  This is not so important for integers
+	 * because overflow is the only bad thing that can happen to
+	 * them, but consider the command  printf %a 1.1
+	 */
+	if (*fmt == 'L') {
+		mod_ldbl = 1;
+		fmt++;
+		if (!strchr("aAeEfFgG", *fmt)) {
+			warnx("bad modifier L for %%%c", *fmt);
+			return (NULL);
+		}
+	} else {
+		mod_ldbl = 0;
+	}
+
+	/* save the current arg offset, and set to the format arg */
+	if (fargv != NULL) {
+		gargv = fargv;
+	}
+
+	convch = *fmt;
+	nextch = *++fmt;
+
+	*fmt = '\0';
+	switch (convch) {
+	case 'b': {
+		size_t len;
+		char *p;
+		int getout;
+
+		p = strdup(getstr());
+		if (p == NULL) {
+			warnx("%s", strerror(ENOMEM));
+			return (NULL);
+		}
+		getout = escape(p, 0, &len);
+		fputs(p, stdout);
+		free(p);
+		if (getout)
+			return (end_fmt);
+		break;
+	}
+	case 'c': {
+		char p;
+
+		p = getchr();
+		PF(start, p);
+		break;
+	}
+	case 's': {
+		const char *p;
+
+		p = getstr();
+		PF(start, p);
+		break;
+	}
+	case 'd': case 'i': case 'o': case 'u': case 'x': case 'X': {
+		char *f;
+		intmax_t val;
+		uintmax_t uval;
+		int signedconv;
+
+		signedconv = (convch == 'd' || convch == 'i');
+		if ((f = mknum(start, convch)) == NULL)
+			return (NULL);
+		if (getnum(&val, &uval, signedconv))
+			*rval = 1;
+		if (signedconv)
+			PF(f, val);
+		else
+			PF(f, uval);
+		break;
+	}
+	case 'e': case 'E':
+	case 'f': case 'F':
+	case 'g': case 'G':
+	case 'a': case 'A': {
+		long double p;
+
+		if (getfloating(&p, mod_ldbl))
+			*rval = 1;
+		if (mod_ldbl)
+			PF(start, p);
+		else
+			PF(start, (double)p);
+		break;
+	}
+	default:
+		warnx("illegal format character %c", convch);
+		return (NULL);
+	}
+	*fmt = nextch;
+	/* return the gargv to the next element */
+	return (fmt);
+}
+
+static char *
+mknum(char *str, char ch)
+{
+	static char *copy;
+	static size_t copy_size;
+	char *newcopy;
+	size_t len, newlen;
+
+	len = strlen(str) + 2;
+	if (len > copy_size) {
+		newlen = ((len + 1023) >> 10) << 10;
+		if ((newcopy = realloc(copy, newlen)) == NULL) {
+			warnx("%s", strerror(ENOMEM));
+			return (NULL);
+		}
+		copy = newcopy;
+		copy_size = newlen;
+	}
+
+	memmove(copy, str, len - 3);
+	copy[len - 3] = 'j';
+	copy[len - 2] = ch;
+	copy[len - 1] = '\0';
+	return (copy);
+}
+
+static int
+escape(char *fmt, int percent, size_t *len)
+{
+	char *save, *store, c;
+	int value;
+
+	for (save = store = fmt; ((c = *fmt) != 0); ++fmt, ++store) {
+		if (c != '\\') {
+			*store = c;
+			continue;
+		}
+		switch (*++fmt) {
+		case '\0':		/* EOS, user error */
+			*store = '\\';
+			*++store = '\0';
+			*len = store - save;
+			return (0);
+		case '\\':		/* backslash */
+		case '\'':		/* single quote */
+			*store = *fmt;
+			break;
+		case 'a':		/* bell/alert */
+			*store = '\a';
+			break;
+		case 'b':		/* backspace */
+			*store = '\b';
+			break;
+		case 'c':
+			if (!percent) {
+				*store = '\0';
+				*len = store - save;
+				return (1);
+			}
+			*store = 'c';
+			break;
+		case 'f':		/* form-feed */
+			*store = '\f';
+			break;
+		case 'n':		/* newline */
+			*store = '\n';
+			break;
+		case 'r':		/* carriage-return */
+			*store = '\r';
+			break;
+		case 't':		/* horizontal tab */
+			*store = '\t';
+			break;
+		case 'v':		/* vertical tab */
+			*store = '\v';
+			break;
+					/* octal constant */
+		case '0': case '1': case '2': case '3':
+		case '4': case '5': case '6': case '7':
+			c = (!percent && *fmt == '0') ? 4 : 3;
+			for (value = 0;
+			    c-- && *fmt >= '0' && *fmt <= '7'; ++fmt) {
+				value <<= 3;
+				value += *fmt - '0';
+			}
+			--fmt;
+			if (percent && value == '%') {
+				*store++ = '%';
+				*store = '%';
+			} else
+				*store = (char)value;
+			break;
+		default:
+			*store = *fmt;
+			break;
+		}
+	}
+	*store = '\0';
+	*len = store - save;
+	return (0);
+}
+
+static int
+getchr(void)
+{
+	if (!*gargv)
+		return ('\0');
+	return ((int)**gargv++);
+}
+
+static const char *
+getstr(void)
+{
+	if (!*gargv)
+		return ("");
+	return (*gargv++);
+}
+
+static int
+getint(int *ip)
+{
+	intmax_t val;
+	uintmax_t uval;
+	int rval;
+
+	if (getnum(&val, &uval, 1))
+		return (1);
+	rval = 0;
+	if (val < INT_MIN || val > INT_MAX) {
+		warnx("%s: %s", *gargv, strerror(ERANGE));
+		rval = 1;
+	}
+	*ip = (int)val;
+	return (rval);
+}
+
+static int
+getnum(intmax_t *ip, uintmax_t *uip, int signedconv)
+{
+	char *ep;
+	int rval;
+
+	if (!*gargv) {
+		*ip = *uip = 0;
+		return (0);
+	}
+	if (**gargv == '"' || **gargv == '\'') {
+		if (signedconv)
+			*ip = asciicode();
+		else
+			*uip = asciicode();
+		return (0);
+	}
+	rval = 0;
+	errno = 0;
+	if (signedconv)
+		*ip = strtoimax(*gargv, &ep, 0);
+	else
+		*uip = strtoumax(*gargv, &ep, 0);
+	if (ep == *gargv) {
+		warnx("%s: expected numeric value", *gargv);
+		rval = 1;
+	}
+	else if (*ep != '\0') {
+		warnx("%s: not completely converted", *gargv);
+		rval = 1;
+	}
+	if (errno == ERANGE) {
+		warnx("%s: %s", *gargv, strerror(ERANGE));
+		rval = 1;
+	}
+	++gargv;
+	return (rval);
+}
+
+static int
+getfloating(long double *dp, int mod_ldbl)
+{
+	char *ep;
+	int rval;
+
+	if (!*gargv) {
+		*dp = 0.0;
+		return (0);
+	}
+	if (**gargv == '"' || **gargv == '\'') {
+		*dp = asciicode();
+		return (0);
+	}
+	rval = 0;
+	errno = 0;
+	if (mod_ldbl)
+		*dp = strtold(*gargv, &ep);
+	else
+		*dp = strtod(*gargv, &ep);
+	if (ep == *gargv) {
+		warnx("%s: expected numeric value", *gargv);
+		rval = 1;
+	} else if (*ep != '\0') {
+		warnx("%s: not completely converted", *gargv);
+		rval = 1;
+	}
+	if (errno == ERANGE) {
+		warnx("%s: %s", *gargv, strerror(ERANGE));
+		rval = 1;
+	}
+	++gargv;
+	return (rval);
+}
+
+static int
+asciicode(void)
+{
+	int ch;
+	wchar_t wch;
+	mbstate_t mbs;
+
+	ch = (unsigned char)**gargv;
+	if (ch == '\'' || ch == '"') {
+		memset(&mbs, 0, sizeof(mbs));
+		switch (mbrtowc(&wch, *gargv + 1, MB_LEN_MAX, &mbs)) {
+		case (size_t)-2:
+		case (size_t)-1:
+			wch = (unsigned char)gargv[0][1];
+			break;
+		case 0:
+			wch = 0;
+			break;
+		}
+		ch = wch;
+	}
+	++gargv;
+	return (ch);
+}
+
+static void
+usage(void)
+{
+	(void)fprintf(stderr, "usage: printf format [arguments ...]\n");
+}
diff --git a/external/sh/redir.c b/external/sh/redir.c
new file mode 100644
index 00000000..0c3653e5
--- /dev/null
+++ b/external/sh/redir.c
@@ -0,0 +1,348 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)redir.c	8.2 (Berkeley) 5/4/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: head/bin/sh/redir.c 272575 2014-10-05 21:51:36Z jilles $");
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <signal.h>
+#include <string.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+/*
+ * Code for dealing with input/output redirection.
+ */
+
+#include "shell.h"
+#include "nodes.h"
+#include "jobs.h"
+#include "expand.h"
+#include "redir.h"
+#include "output.h"
+#include "memalloc.h"
+#include "error.h"
+#include "options.h"
+
+
+#define EMPTY -2		/* marks an unused slot in redirtab */
+#define CLOSED -1		/* fd was not open before redir */
+
+
+struct redirtab {
+	struct redirtab *next;
+	int renamed[10];
+	int fd0_redirected;
+};
+
+
+static struct redirtab *redirlist;
+
+/*
+ * We keep track of whether or not fd0 has been redirected.  This is for
+ * background commands, where we want to redirect fd0 to /dev/null only
+ * if it hasn't already been redirected.
+*/
+static int fd0_redirected = 0;
+
+static void openredirect(union node *, char[10 ]);
+static int openhere(union node *);
+
+
+/*
+ * Process a list of redirection commands.  If the REDIR_PUSH flag is set,
+ * old file descriptors are stashed away so that the redirection can be
+ * undone by calling popredir.  If the REDIR_BACKQ flag is set, then the
+ * standard output, and the standard error if it becomes a duplicate of
+ * stdout, is saved in memory.
+*
+ * We suppress interrupts so that we won't leave open file
+ * descriptors around.  Because the signal handler remains
+ * installed and we do not use system call restart, interrupts
+ * will still abort blocking opens such as fifos (they will fail
+ * with EINTR). There is, however, a race condition if an interrupt
+ * arrives after INTOFF and before open blocks.
+ */
+
+void
+redirect(union node *redir, int flags)
+{
+	union node *n;
+	struct redirtab *sv = NULL;
+	int i;
+	int fd;
+	char memory[10];	/* file descriptors to write to memory */
+
+	INTOFF;
+	for (i = 10 ; --i >= 0 ; )
+		memory[i] = 0;
+	memory[1] = flags & REDIR_BACKQ;
+	if (flags & REDIR_PUSH) {
+		sv = ckmalloc(sizeof (struct redirtab));
+		for (i = 0 ; i < 10 ; i++)
+			sv->renamed[i] = EMPTY;
+		sv->fd0_redirected = fd0_redirected;
+		sv->next = redirlist;
+		redirlist = sv;
+	}
+	for (n = redir ; n ; n = n->nfile.next) {
+		fd = n->nfile.fd;
+		if (fd == 0)
+			fd0_redirected = 1;
+		if ((n->nfile.type == NTOFD || n->nfile.type == NFROMFD) &&
+		    n->ndup.dupfd == fd)
+			continue; /* redirect from/to same file descriptor */
+
+		if ((flags & REDIR_PUSH) && sv->renamed[fd] == EMPTY) {
+			INTOFF;
+			if ((i = fcntl(fd, F_DUPFD_CLOEXEC, 10)) == -1) {
+				switch (errno) {
+				case EBADF:
+					i = CLOSED;
+					break;
+				default:
+					INTON;
+					error("%d: %s", fd, strerror(errno));
+					break;
+				}
+			}
+			sv->renamed[fd] = i;
+			INTON;
+		}
+		openredirect(n, memory);
+		INTON;
+		INTOFF;
+	}
+	if (memory[1])
+		out1 = &memout;
+	if (memory[2])
+		out2 = &memout;
+	INTON;
+}
+
+
+static void
+openredirect(union node *redir, char memory[10])
+{
+	struct stat sb;
+	int fd = redir->nfile.fd;
+	const char *fname;
+	int f;
+	int e;
+
+	memory[fd] = 0;
+	switch (redir->nfile.type) {
+	case NFROM:
+		fname = redir->nfile.expfname;
+		if ((f = open(fname, O_RDONLY)) < 0)
+			error("cannot open %s: %s", fname, strerror(errno));
+		break;
+	case NFROMTO:
+		fname = redir->nfile.expfname;
+		if ((f = open(fname, O_RDWR|O_CREAT, 0666)) < 0)
+			error("cannot create %s: %s", fname, strerror(errno));
+		break;
+	case NTO:
+		if (Cflag) {
+			fname = redir->nfile.expfname;
+			if (stat(fname, &sb) == -1) {
+				if ((f = open(fname, O_WRONLY|O_CREAT|O_EXCL, 0666)) < 0)
+					error("cannot create %s: %s", fname, strerror(errno));
+			} else if (!S_ISREG(sb.st_mode)) {
+				if ((f = open(fname, O_WRONLY, 0666)) < 0)
+					error("cannot create %s: %s", fname, strerror(errno));
+				if (fstat(f, &sb) != -1 && S_ISREG(sb.st_mode)) {
+					close(f);
+					error("cannot create %s: %s", fname,
+					    strerror(EEXIST));
+				}
+			} else
+				error("cannot create %s: %s", fname,
+				    strerror(EEXIST));
+			break;
+		}
+		/* FALLTHROUGH */
+	case NCLOBBER:
+		fname = redir->nfile.expfname;
+		if ((f = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0)
+			error("cannot create %s: %s", fname, strerror(errno));
+		break;
+	case NAPPEND:
+		fname = redir->nfile.expfname;
+		if ((f = open(fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0)
+			error("cannot create %s: %s", fname, strerror(errno));
+		break;
+	case NTOFD:
+	case NFROMFD:
+		if (redir->ndup.dupfd >= 0) {	/* if not ">&-" */
+			if (memory[redir->ndup.dupfd])
+				memory[fd] = 1;
+			else {
+				if (dup2(redir->ndup.dupfd, fd) < 0)
+					error("%d: %s", redir->ndup.dupfd,
+							strerror(errno));
+			}
+		} else {
+			close(fd);
+		}
+		return;
+	case NHERE:
+	case NXHERE:
+		f = openhere(redir);
+		break;
+	default:
+		abort();
+	}
+	if (f != fd) {
+		if (dup2(f, fd) == -1) {
+			e = errno;
+			close(f);
+			error("%d: %s", fd, strerror(e));
+		}
+		close(f);
+	}
+}
+
+
+/*
+ * Handle here documents.  Normally we fork off a process to write the
+ * data to a pipe.  If the document is short, we can stuff the data in
+ * the pipe without forking.
+ */
+
+static int
+openhere(union node *redir)
+{
+	const char *p;
+	int pip[2];
+	size_t len = 0;
+	int flags;
+	ssize_t written = 0;
+
+	if (pipe(pip) < 0)
+		error("Pipe call failed: %s", strerror(errno));
+
+	if (redir->type == NXHERE)
+		p = redir->nhere.expdoc;
+	else
+		p = redir->nhere.doc->narg.text;
+	len = strlen(p);
+	if (len == 0)
+		goto out;
+	flags = fcntl(pip[1], F_GETFL, 0);
+	if (flags != -1 && fcntl(pip[1], F_SETFL, flags | O_NONBLOCK) != -1) {
+		written = write(pip[1], p, len);
+		if (written < 0)
+			written = 0;
+		if ((size_t)written == len)
+			goto out;
+		fcntl(pip[1], F_SETFL, flags);
+	}
+
+	if (forkshell((struct job *)NULL, (union node *)NULL, FORK_NOJOB) == 0) {
+		close(pip[0]);
+		signal(SIGINT, SIG_IGN);
+		signal(SIGQUIT, SIG_IGN);
+		signal(SIGHUP, SIG_IGN);
+		signal(SIGTSTP, SIG_IGN);
+		signal(SIGPIPE, SIG_DFL);
+		xwrite(pip[1], p + written, len - written);
+		_exit(0);
+	}
+out:
+	close(pip[1]);
+	return pip[0];
+}
+
+
+
+/*
+ * Undo the effects of the last redirection.
+ */
+
+void
+popredir(void)
+{
+	struct redirtab *rp = redirlist;
+	int i;
+
+	for (i = 0 ; i < 10 ; i++) {
+		if (rp->renamed[i] != EMPTY) {
+			if (rp->renamed[i] >= 0) {
+				dup2(rp->renamed[i], i);
+				close(rp->renamed[i]);
+			} else {
+				close(i);
+			}
+		}
+	}
+	INTOFF;
+	fd0_redirected = rp->fd0_redirected;
+	redirlist = rp->next;
+	ckfree(rp);
+	INTON;
+}
+
+/* Return true if fd 0 has already been redirected at least once.  */
+int
+fd0_redirected_p(void)
+{
+        return fd0_redirected != 0;
+}
+
+/*
+ * Discard all saved file descriptors.
+ */
+
+void
+clearredir(void)
+{
+	struct redirtab *rp;
+	int i;
+
+	for (rp = redirlist ; rp ; rp = rp->next) {
+		for (i = 0 ; i < 10 ; i++) {
+			if (rp->renamed[i] >= 0) {
+				close(rp->renamed[i]);
+			}
+			rp->renamed[i] = EMPTY;
+		}
+	}
+}
diff --git a/external/sh/redir.h b/external/sh/redir.h
new file mode 100644
index 00000000..7146dd1f
--- /dev/null
+++ b/external/sh/redir.h
@@ -0,0 +1,45 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)redir.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: head/bin/sh/redir.h 254426 2013-08-16 20:24:41Z jilles $
+ */
+
+/* flags passed to redirect */
+#define REDIR_PUSH 01		/* save previous values of file descriptors */
+#define REDIR_BACKQ 02		/* save the command output in memory */
+
+union node;
+void redirect(union node *, int);
+void popredir(void);
+int fd0_redirected_p(void);
+void clearredir(void);
+
diff --git a/external/sh/shell.h b/external/sh/shell.h
new file mode 100644
index 00000000..add2bd87
--- /dev/null
+++ b/external/sh/shell.h
@@ -0,0 +1,77 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)shell.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: head/bin/sh/shell.h 253658 2013-07-25 19:48:15Z jilles $
+ */
+
+#ifndef SHELL_H_
+#define SHELL_H_
+
+#include <inttypes.h>
+
+/*
+ * The follow should be set to reflect the type of system you have:
+ *	JOBS -> 1 if you have Berkeley job control, 0 otherwise.
+ *	define DEBUG=1 to compile in debugging (set global "debug" to turn on)
+ *	define DEBUG=2 to compile in and turn on debugging.
+ *
+ * When debugging is on, debugging info will be written to ./trace and
+ * a quit signal will generate a core dump.
+ */
+
+
+#define	JOBS 1
+/* #define DEBUG 1 */
+
+/*
+ * Type of used arithmetics. SUSv3 requires us to have at least signed long.
+ */
+typedef intmax_t arith_t;
+#define	ARITH_FORMAT_STR  "%" PRIdMAX
+#define	atoarith_t(arg)  strtoimax(arg, NULL, 0)
+#define	strtoarith_t(nptr, endptr, base)  strtoimax(nptr, endptr, base)
+#define	ARITH_MIN INTMAX_MIN
+#define	ARITH_MAX INTMAX_MAX
+
+typedef void *pointer;
+
+#include <sys/cdefs.h>
+
+extern char nullstr[1];		/* null string */
+
+#ifdef DEBUG
+#define TRACE(param)  sh_trace param
+#else
+#define TRACE(param)
+#endif
+
+#endif /* !SHELL_H_ */
diff --git a/external/sh/show.c b/external/sh/show.c
new file mode 100644
index 00000000..0e8cf433
--- /dev/null
+++ b/external/sh/show.c
@@ -0,0 +1,408 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)show.c	8.3 (Berkeley) 5/4/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: head/bin/sh/show.c 258776 2013-11-30 21:27:11Z jilles $");
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <errno.h>
+
+#include "shell.h"
+#include "parser.h"
+#include "nodes.h"
+#include "mystring.h"
+#include "show.h"
+
+
+#ifdef DEBUG
+static void shtree(union node *, int, char *, FILE*);
+static void shcmd(union node *, FILE *);
+static void sharg(union node *, FILE *);
+static void indent(int, char *, FILE *);
+static void trstring(char *);
+
+
+void
+showtree(union node *n)
+{
+	trputs("showtree called\n");
+	shtree(n, 1, NULL, stdout);
+}
+
+
+static void
+shtree(union node *n, int ind, char *pfx, FILE *fp)
+{
+	struct nodelist *lp;
+	char *s;
+
+	if (n == NULL)
+		return;
+
+	indent(ind, pfx, fp);
+	switch(n->type) {
+	case NSEMI:
+		s = "; ";
+		goto binop;
+	case NAND:
+		s = " && ";
+		goto binop;
+	case NOR:
+		s = " || ";
+binop:
+		shtree(n->nbinary.ch1, ind, NULL, fp);
+	   /*    if (ind < 0) */
+			fputs(s, fp);
+		shtree(n->nbinary.ch2, ind, NULL, fp);
+		break;
+	case NCMD:
+		shcmd(n, fp);
+		if (ind >= 0)
+			putc('\n', fp);
+		break;
+	case NPIPE:
+		for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
+			shcmd(lp->n, fp);
+			if (lp->next)
+				fputs(" | ", fp);
+		}
+		if (n->npipe.backgnd)
+			fputs(" &", fp);
+		if (ind >= 0)
+			putc('\n', fp);
+		break;
+	default:
+		fprintf(fp, "<node type %d>", n->type);
+		if (ind >= 0)
+			putc('\n', fp);
+		break;
+	}
+}
+
+
+
+static void
+shcmd(union node *cmd, FILE *fp)
+{
+	union node *np;
+	int first;
+	char *s;
+	int dftfd;
+
+	first = 1;
+	for (np = cmd->ncmd.args ; np ; np = np->narg.next) {
+		if (! first)
+			putchar(' ');
+		sharg(np, fp);
+		first = 0;
+	}
+	for (np = cmd->ncmd.redirect ; np ; np = np->nfile.next) {
+		if (! first)
+			putchar(' ');
+		switch (np->nfile.type) {
+			case NTO:	s = ">";  dftfd = 1; break;
+			case NAPPEND:	s = ">>"; dftfd = 1; break;
+			case NTOFD:	s = ">&"; dftfd = 1; break;
+			case NCLOBBER:	s = ">|"; dftfd = 1; break;
+			case NFROM:	s = "<";  dftfd = 0; break;
+			case NFROMTO:	s = "<>"; dftfd = 0; break;
+			case NFROMFD:	s = "<&"; dftfd = 0; break;
+			case NHERE:	s = "<<"; dftfd = 0; break;
+			case NXHERE:	s = "<<"; dftfd = 0; break;
+			default:  	s = "*error*"; dftfd = 0; break;
+		}
+		if (np->nfile.fd != dftfd)
+			fprintf(fp, "%d", np->nfile.fd);
+		fputs(s, fp);
+		if (np->nfile.type == NTOFD || np->nfile.type == NFROMFD) {
+			if (np->ndup.dupfd >= 0)
+				fprintf(fp, "%d", np->ndup.dupfd);
+			else
+				fprintf(fp, "-");
+		} else if (np->nfile.type == NHERE) {
+				fprintf(fp, "HERE");
+		} else if (np->nfile.type == NXHERE) {
+				fprintf(fp, "XHERE");
+		} else {
+			sharg(np->nfile.fname, fp);
+		}
+		first = 0;
+	}
+}
+
+
+
+static void
+sharg(union node *arg, FILE *fp)
+{
+	char *p;
+	struct nodelist *bqlist;
+	int subtype;
+
+	if (arg->type != NARG) {
+		printf("<node type %d>\n", arg->type);
+		fflush(stdout);
+		abort();
+	}
+	bqlist = arg->narg.backquote;
+	for (p = arg->narg.text ; *p ; p++) {
+		switch (*p) {
+		case CTLESC:
+			putc(*++p, fp);
+			break;
+		case CTLVAR:
+			putc('$', fp);
+			putc('{', fp);
+			subtype = *++p;
+			if (subtype == VSLENGTH)
+				putc('#', fp);
+
+			while (*p != '=')
+				putc(*p++, fp);
+
+			if (subtype & VSNUL)
+				putc(':', fp);
+
+			switch (subtype & VSTYPE) {
+			case VSNORMAL:
+				putc('}', fp);
+				break;
+			case VSMINUS:
+				putc('-', fp);
+				break;
+			case VSPLUS:
+				putc('+', fp);
+				break;
+			case VSQUESTION:
+				putc('?', fp);
+				break;
+			case VSASSIGN:
+				putc('=', fp);
+				break;
+			case VSTRIMLEFT:
+				putc('#', fp);
+				break;
+			case VSTRIMLEFTMAX:
+				putc('#', fp);
+				putc('#', fp);
+				break;
+			case VSTRIMRIGHT:
+				putc('%', fp);
+				break;
+			case VSTRIMRIGHTMAX:
+				putc('%', fp);
+				putc('%', fp);
+				break;
+			case VSLENGTH:
+				break;
+			default:
+				printf("<subtype %d>", subtype);
+			}
+			break;
+		case CTLENDVAR:
+		     putc('}', fp);
+		     break;
+		case CTLBACKQ:
+		case CTLBACKQ|CTLQUOTE:
+			putc('$', fp);
+			putc('(', fp);
+			shtree(bqlist->n, -1, NULL, fp);
+			putc(')', fp);
+			break;
+		default:
+			putc(*p, fp);
+			break;
+		}
+	}
+}
+
+
+static void
+indent(int amount, char *pfx, FILE *fp)
+{
+	int i;
+
+	for (i = 0 ; i < amount ; i++) {
+		if (pfx && i == amount - 1)
+			fputs(pfx, fp);
+		putc('\t', fp);
+	}
+}
+
+
+/*
+ * Debugging stuff.
+ */
+
+
+FILE *tracefile;
+
+#if DEBUG >= 2
+int debug = 1;
+#else
+int debug = 0;
+#endif
+
+
+void
+trputc(int c)
+{
+	if (tracefile == NULL)
+		return;
+	putc(c, tracefile);
+	if (c == '\n')
+		fflush(tracefile);
+}
+
+
+void
+sh_trace(const char *fmt, ...)
+{
+	va_list va;
+	va_start(va, fmt);
+	if (tracefile != NULL) {
+		(void) vfprintf(tracefile, fmt, va);
+		if (strchr(fmt, '\n'))
+			(void) fflush(tracefile);
+	}
+	va_end(va);
+}
+
+
+void
+trputs(const char *s)
+{
+	if (tracefile == NULL)
+		return;
+	fputs(s, tracefile);
+	if (strchr(s, '\n'))
+		fflush(tracefile);
+}
+
+
+static void
+trstring(char *s)
+{
+	char *p;
+	char c;
+
+	if (tracefile == NULL)
+		return;
+	putc('"', tracefile);
+	for (p = s ; *p ; p++) {
+		switch (*p) {
+		case '\n':  c = 'n';  goto backslash;
+		case '\t':  c = 't';  goto backslash;
+		case '\r':  c = 'r';  goto backslash;
+		case '"':  c = '"';  goto backslash;
+		case '\\':  c = '\\';  goto backslash;
+		case CTLESC:  c = 'e';  goto backslash;
+		case CTLVAR:  c = 'v';  goto backslash;
+		case CTLVAR+CTLQUOTE:  c = 'V';  goto backslash;
+		case CTLBACKQ:  c = 'q';  goto backslash;
+		case CTLBACKQ+CTLQUOTE:  c = 'Q';  goto backslash;
+backslash:	  putc('\\', tracefile);
+			putc(c, tracefile);
+			break;
+		default:
+			if (*p >= ' ' && *p <= '~')
+				putc(*p, tracefile);
+			else {
+				putc('\\', tracefile);
+				putc(*p >> 6 & 03, tracefile);
+				putc(*p >> 3 & 07, tracefile);
+				putc(*p & 07, tracefile);
+			}
+			break;
+		}
+	}
+	putc('"', tracefile);
+}
+
+
+void
+trargs(char **ap)
+{
+	if (tracefile == NULL)
+		return;
+	while (*ap) {
+		trstring(*ap++);
+		if (*ap)
+			putc(' ', tracefile);
+		else
+			putc('\n', tracefile);
+	}
+	fflush(tracefile);
+}
+
+
+void
+opentrace(void)
+{
+	char s[100];
+	int flags;
+
+	if (!debug)
+		return;
+#ifdef not_this_way
+	{
+		char *p;
+		if ((p = getenv("HOME")) == NULL) {
+			if (geteuid() == 0)
+				p = "/";
+			else
+				p = "/tmp";
+		}
+		strcpy(s, p);
+		strcat(s, "/trace");
+	}
+#else
+	strcpy(s, "./trace");
+#endif /* not_this_way */
+	if ((tracefile = fopen(s, "a")) == NULL) {
+		fprintf(stderr, "Can't open %s: %s\n", s, strerror(errno));
+		return;
+	}
+	if ((flags = fcntl(fileno(tracefile), F_GETFL, 0)) >= 0)
+		fcntl(fileno(tracefile), F_SETFL, flags | O_APPEND);
+	fputs("\nTracing started.\n", tracefile);
+	fflush(tracefile);
+}
+#endif /* DEBUG */
diff --git a/external/sh/show.h b/external/sh/show.h
new file mode 100644
index 00000000..d9b16669
--- /dev/null
+++ b/external/sh/show.h
@@ -0,0 +1,40 @@
+/*-
+ * Copyright (c) 1995
+ *      The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)show.h	1.1 (Berkeley) 5/4/95
+ * $FreeBSD: head/bin/sh/show.h 200956 2009-12-24 18:41:14Z jilles $
+ */
+
+void showtree(union node *);
+#ifdef DEBUG
+void sh_trace(const char *, ...) __printflike(1, 2);
+void trargs(char **);
+void trputc(int);
+void trputs(const char *);
+void opentrace(void);
+#endif
diff --git a/external/sh/syntax.c b/external/sh/syntax.c
new file mode 100644
index 00000000..28f9b62d
--- /dev/null
+++ b/external/sh/syntax.c
@@ -0,0 +1,192 @@
+/*
+ * This file was generated by the mksyntax program.
+ */
+
+#include "parser.h"
+#include "shell.h"
+#include "syntax.h"
+
+/* syntax table used when not in quotes */
+const char basesyntax[SYNBASE + CHAR_MAX + 1] = {
+	[SYNBASE + PEOF] = CEOF,
+	[SYNBASE + CTLESC] = CCTL,
+	[SYNBASE + CTLVAR] = CCTL,
+	[SYNBASE + CTLENDVAR] = CCTL,
+	[SYNBASE + CTLBACKQ] = CCTL,
+	[SYNBASE + CTLBACKQ + CTLQUOTE] = CCTL,
+	[SYNBASE + CTLARI] = CCTL,
+	[SYNBASE + CTLENDARI] = CCTL,
+	[SYNBASE + CTLQUOTEMARK] = CCTL,
+	[SYNBASE + CTLQUOTEEND] = CCTL,
+	[SYNBASE + '\n'] = CNL,
+	[SYNBASE + '\\'] = CBACK,
+	[SYNBASE + '\''] = CSQUOTE,
+	[SYNBASE + '"'] = CDQUOTE,
+	[SYNBASE + '`'] = CBQUOTE,
+	[SYNBASE + '$'] = CVAR,
+	[SYNBASE + '}'] = CENDVAR,
+	[SYNBASE + '<'] = CSPCL,
+	[SYNBASE + '>'] = CSPCL,
+	[SYNBASE + '('] = CSPCL,
+	[SYNBASE + ')'] = CSPCL,
+	[SYNBASE + ';'] = CSPCL,
+	[SYNBASE + '&'] = CSPCL,
+	[SYNBASE + '|'] = CSPCL,
+	[SYNBASE + ' '] = CSPCL,
+	[SYNBASE + '\t'] = CSPCL,
+};
+
+/* syntax table used when in double quotes */
+const char dqsyntax[SYNBASE + CHAR_MAX + 1] = {
+	[SYNBASE + PEOF] = CEOF,
+	[SYNBASE + CTLESC] = CCTL,
+	[SYNBASE + CTLVAR] = CCTL,
+	[SYNBASE + CTLENDVAR] = CCTL,
+	[SYNBASE + CTLBACKQ] = CCTL,
+	[SYNBASE + CTLBACKQ + CTLQUOTE] = CCTL,
+	[SYNBASE + CTLARI] = CCTL,
+	[SYNBASE + CTLENDARI] = CCTL,
+	[SYNBASE + CTLQUOTEMARK] = CCTL,
+	[SYNBASE + CTLQUOTEEND] = CCTL,
+	[SYNBASE + '\n'] = CNL,
+	[SYNBASE + '\\'] = CBACK,
+	[SYNBASE + '"'] = CENDQUOTE,
+	[SYNBASE + '`'] = CBQUOTE,
+	[SYNBASE + '$'] = CVAR,
+	[SYNBASE + '}'] = CENDVAR,
+	[SYNBASE + '!'] = CCTL,
+	[SYNBASE + '*'] = CCTL,
+	[SYNBASE + '?'] = CCTL,
+	[SYNBASE + '['] = CCTL,
+	[SYNBASE + ']'] = CCTL,
+	[SYNBASE + '='] = CCTL,
+	[SYNBASE + '~'] = CCTL,
+	[SYNBASE + ':'] = CCTL,
+	[SYNBASE + '/'] = CCTL,
+	[SYNBASE + '-'] = CCTL,
+	[SYNBASE + '^'] = CCTL,
+};
+
+/* syntax table used when in single quotes */
+const char sqsyntax[SYNBASE + CHAR_MAX + 1] = {
+	[SYNBASE + PEOF] = CEOF,
+	[SYNBASE + CTLESC] = CCTL,
+	[SYNBASE + CTLVAR] = CCTL,
+	[SYNBASE + CTLENDVAR] = CCTL,
+	[SYNBASE + CTLBACKQ] = CCTL,
+	[SYNBASE + CTLBACKQ + CTLQUOTE] = CCTL,
+	[SYNBASE + CTLARI] = CCTL,
+	[SYNBASE + CTLENDARI] = CCTL,
+	[SYNBASE + CTLQUOTEMARK] = CCTL,
+	[SYNBASE + CTLQUOTEEND] = CCTL,
+	[SYNBASE + '\n'] = CNL,
+	[SYNBASE + '\\'] = CSBACK,
+	[SYNBASE + '\''] = CENDQUOTE,
+	[SYNBASE + '!'] = CCTL,
+	[SYNBASE + '*'] = CCTL,
+	[SYNBASE + '?'] = CCTL,
+	[SYNBASE + '['] = CCTL,
+	[SYNBASE + ']'] = CCTL,
+	[SYNBASE + '='] = CCTL,
+	[SYNBASE + '~'] = CCTL,
+	[SYNBASE + ':'] = CCTL,
+	[SYNBASE + '/'] = CCTL,
+	[SYNBASE + '-'] = CCTL,
+	[SYNBASE + '^'] = CCTL,
+};
+
+/* syntax table used when in arithmetic */
+const char arisyntax[SYNBASE + CHAR_MAX + 1] = {
+	[SYNBASE + PEOF] = CEOF,
+	[SYNBASE + CTLESC] = CCTL,
+	[SYNBASE + CTLVAR] = CCTL,
+	[SYNBASE + CTLENDVAR] = CCTL,
+	[SYNBASE + CTLBACKQ] = CCTL,
+	[SYNBASE + CTLBACKQ + CTLQUOTE] = CCTL,
+	[SYNBASE + CTLARI] = CCTL,
+	[SYNBASE + CTLENDARI] = CCTL,
+	[SYNBASE + CTLQUOTEMARK] = CCTL,
+	[SYNBASE + CTLQUOTEEND] = CCTL,
+	[SYNBASE + '\n'] = CNL,
+	[SYNBASE + '\\'] = CBACK,
+	[SYNBASE + '`'] = CBQUOTE,
+	[SYNBASE + '"'] = CIGN,
+	[SYNBASE + '$'] = CVAR,
+	[SYNBASE + '}'] = CENDVAR,
+	[SYNBASE + '('] = CLP,
+	[SYNBASE + ')'] = CRP,
+};
+
+/* character classification table */
+const char is_type[SYNBASE + CHAR_MAX + 1] = {
+	[SYNBASE + '0'] = ISDIGIT,
+	[SYNBASE + '1'] = ISDIGIT,
+	[SYNBASE + '2'] = ISDIGIT,
+	[SYNBASE + '3'] = ISDIGIT,
+	[SYNBASE + '4'] = ISDIGIT,
+	[SYNBASE + '5'] = ISDIGIT,
+	[SYNBASE + '6'] = ISDIGIT,
+	[SYNBASE + '7'] = ISDIGIT,
+	[SYNBASE + '8'] = ISDIGIT,
+	[SYNBASE + '9'] = ISDIGIT,
+	[SYNBASE + 'a'] = ISLOWER,
+	[SYNBASE + 'b'] = ISLOWER,
+	[SYNBASE + 'c'] = ISLOWER,
+	[SYNBASE + 'd'] = ISLOWER,
+	[SYNBASE + 'e'] = ISLOWER,
+	[SYNBASE + 'f'] = ISLOWER,
+	[SYNBASE + 'g'] = ISLOWER,
+	[SYNBASE + 'h'] = ISLOWER,
+	[SYNBASE + 'i'] = ISLOWER,
+	[SYNBASE + 'j'] = ISLOWER,
+	[SYNBASE + 'k'] = ISLOWER,
+	[SYNBASE + 'l'] = ISLOWER,
+	[SYNBASE + 'm'] = ISLOWER,
+	[SYNBASE + 'n'] = ISLOWER,
+	[SYNBASE + 'o'] = ISLOWER,
+	[SYNBASE + 'p'] = ISLOWER,
+	[SYNBASE + 'q'] = ISLOWER,
+	[SYNBASE + 'r'] = ISLOWER,
+	[SYNBASE + 's'] = ISLOWER,
+	[SYNBASE + 't'] = ISLOWER,
+	[SYNBASE + 'u'] = ISLOWER,
+	[SYNBASE + 'v'] = ISLOWER,
+	[SYNBASE + 'w'] = ISLOWER,
+	[SYNBASE + 'x'] = ISLOWER,
+	[SYNBASE + 'y'] = ISLOWER,
+	[SYNBASE + 'z'] = ISLOWER,
+	[SYNBASE + 'A'] = ISUPPER,
+	[SYNBASE + 'B'] = ISUPPER,
+	[SYNBASE + 'C'] = ISUPPER,
+	[SYNBASE + 'D'] = ISUPPER,
+	[SYNBASE + 'E'] = ISUPPER,
+	[SYNBASE + 'F'] = ISUPPER,
+	[SYNBASE + 'G'] = ISUPPER,
+	[SYNBASE + 'H'] = ISUPPER,
+	[SYNBASE + 'I'] = ISUPPER,
+	[SYNBASE + 'J'] = ISUPPER,
+	[SYNBASE + 'K'] = ISUPPER,
+	[SYNBASE + 'L'] = ISUPPER,
+	[SYNBASE + 'M'] = ISUPPER,
+	[SYNBASE + 'N'] = ISUPPER,
+	[SYNBASE + 'O'] = ISUPPER,
+	[SYNBASE + 'P'] = ISUPPER,
+	[SYNBASE + 'Q'] = ISUPPER,
+	[SYNBASE + 'R'] = ISUPPER,
+	[SYNBASE + 'S'] = ISUPPER,
+	[SYNBASE + 'T'] = ISUPPER,
+	[SYNBASE + 'U'] = ISUPPER,
+	[SYNBASE + 'V'] = ISUPPER,
+	[SYNBASE + 'W'] = ISUPPER,
+	[SYNBASE + 'X'] = ISUPPER,
+	[SYNBASE + 'Y'] = ISUPPER,
+	[SYNBASE + 'Z'] = ISUPPER,
+	[SYNBASE + '_'] = ISUNDER,
+	[SYNBASE + '#'] = ISSPECL,
+	[SYNBASE + '?'] = ISSPECL,
+	[SYNBASE + '$'] = ISSPECL,
+	[SYNBASE + '!'] = ISSPECL,
+	[SYNBASE + '-'] = ISSPECL,
+	[SYNBASE + '*'] = ISSPECL,
+	[SYNBASE + '@'] = ISSPECL,
+};
diff --git a/external/sh/syntax.h b/external/sh/syntax.h
new file mode 100644
index 00000000..e9cf2e90
--- /dev/null
+++ b/external/sh/syntax.h
@@ -0,0 +1,54 @@
+/*
+ * This file was generated by the mksyntax program.
+ */
+
+#include <sys/cdefs.h>
+#include <limits.h>
+
+/* Syntax classes */
+#define CWORD 0			/* character is nothing special */
+#define CNL 1			/* newline character */
+#define CBACK 2			/* a backslash character */
+#define CSBACK 3		/* a backslash character in single quotes */
+#define CSQUOTE 4		/* single quote */
+#define CDQUOTE 5		/* double quote */
+#define CENDQUOTE 6		/* a terminating quote */
+#define CBQUOTE 7		/* backwards single quote */
+#define CVAR 8			/* a dollar sign */
+#define CENDVAR 9		/* a '}' character */
+#define CLP 10			/* a left paren in arithmetic */
+#define CRP 11			/* a right paren in arithmetic */
+#define CEOF 12			/* end of file */
+#define CCTL 13			/* like CWORD, except it must be escaped */
+#define CSPCL 14		/* these terminate a word */
+#define CIGN 15			/* character should be ignored */
+
+/* Syntax classes for is_ functions */
+#define ISDIGIT 01		/* a digit */
+#define ISUPPER 02		/* an upper case letter */
+#define ISLOWER 04		/* a lower case letter */
+#define ISUNDER 010		/* an underscore */
+#define ISSPECL 020		/* the name of a special parameter */
+
+#define SYNBASE (1 - CHAR_MIN)
+#define PEOF -SYNBASE
+
+
+#define BASESYNTAX (basesyntax + SYNBASE)
+#define DQSYNTAX (dqsyntax + SYNBASE)
+#define SQSYNTAX (sqsyntax + SYNBASE)
+#define ARISYNTAX (arisyntax + SYNBASE)
+
+#define is_digit(c)	((unsigned int)((c) - '0') <= 9)
+#define is_eof(c)	((c) == PEOF)
+#define is_alpha(c)	((is_type+SYNBASE)[(int)c] & (ISUPPER|ISLOWER))
+#define is_name(c)	((is_type+SYNBASE)[(int)c] & (ISUPPER|ISLOWER|ISUNDER))
+#define is_in_name(c)	((is_type+SYNBASE)[(int)c] & (ISUPPER|ISLOWER|ISUNDER|ISDIGIT))
+#define is_special(c)	((is_type+SYNBASE)[(int)c] & (ISSPECL|ISDIGIT))
+#define digit_val(c)	((c) - '0')
+
+extern const char basesyntax[];
+extern const char dqsyntax[];
+extern const char sqsyntax[];
+extern const char arisyntax[];
+extern const char is_type[];
diff --git a/external/sh/test.c b/external/sh/test.c
new file mode 100644
index 00000000..446c0a93
--- /dev/null
+++ b/external/sh/test.c
@@ -0,0 +1,599 @@
+/*	$NetBSD: test.c,v 1.21 1999/04/05 09:48:38 kleink Exp $	*/
+
+/*-
+ * test(1); version 7-like  --  author Erik Baalbergen
+ * modified by Eric Gisin to be used as built-in.
+ * modified by Arnold Robbins to add SVR3 compatibility
+ * (-x -c -b -p -u -g -k) plus Korn's -L -nt -ot -ef and new -S (socket).
+ * modified by J.T. Conklin for NetBSD.
+ *
+ * This program is in the Public Domain.
+ */
+/*
+ * Important: This file is used both as a standalone program /bin/test and
+ * as a builtin for /bin/sh (#define SHELL).
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: head/bin/test/test.c 259017 2013-12-05 22:53:32Z jilles $");
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <ctype.h>
+#include <err.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <limits.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#ifdef SHELL
+#define main testcmd
+#include "bltin/bltin.h"
+#else
+#include <locale.h>
+
+static void error(const char *, ...) __dead2 __printf0like(1, 2);
+
+static void
+error(const char *msg, ...)
+{
+	va_list ap;
+	va_start(ap, msg);
+	verrx(2, msg, ap);
+	/*NOTREACHED*/
+	va_end(ap);
+}
+#endif
+
+/* test(1) accepts the following grammar:
+	oexpr	::= aexpr | aexpr "-o" oexpr ;
+	aexpr	::= nexpr | nexpr "-a" aexpr ;
+	nexpr	::= primary | "!" primary
+	primary	::= unary-operator operand
+		| operand binary-operator operand
+		| operand
+		| "(" oexpr ")"
+		;
+	unary-operator ::= "-r"|"-w"|"-x"|"-f"|"-d"|"-c"|"-b"|"-p"|
+		"-u"|"-g"|"-k"|"-s"|"-t"|"-z"|"-n"|"-o"|"-O"|"-G"|"-L"|"-S";
+
+	binary-operator ::= "="|"!="|"-eq"|"-ne"|"-ge"|"-gt"|"-le"|"-lt"|
+			"-nt"|"-ot"|"-ef";
+	operand ::= <any legal UNIX file name>
+*/
+
+enum token_types {
+	UNOP = 0x100,
+	BINOP = 0x200,
+	BUNOP = 0x300,
+	BBINOP = 0x400,
+	PAREN = 0x500
+};
+
+enum token {
+	EOI,
+	OPERAND,
+	FILRD = UNOP + 1,
+	FILWR,
+	FILEX,
+	FILEXIST,
+	FILREG,
+	FILDIR,
+	FILCDEV,
+	FILBDEV,
+	FILFIFO,
+	FILSOCK,
+	FILSYM,
+	FILGZ,
+	FILTT,
+	FILSUID,
+	FILSGID,
+	FILSTCK,
+	STREZ,
+	STRNZ,
+	FILUID,
+	FILGID,
+	FILNT = BINOP + 1,
+	FILOT,
+	FILEQ,
+	STREQ,
+	STRNE,
+	STRLT,
+	STRGT,
+	INTEQ,
+	INTNE,
+	INTGE,
+	INTGT,
+	INTLE,
+	INTLT,
+	UNOT = BUNOP + 1,
+	BAND = BBINOP + 1,
+	BOR,
+	LPAREN = PAREN + 1,
+	RPAREN
+};
+
+#define TOKEN_TYPE(token) ((token) & 0xff00)
+
+static struct t_op {
+	char op_text[4];
+	short op_num;
+} const ops [] = {
+	{"-r",	FILRD},
+	{"-w",	FILWR},
+	{"-x",	FILEX},
+	{"-e",	FILEXIST},
+	{"-f",	FILREG},
+	{"-d",	FILDIR},
+	{"-c",	FILCDEV},
+	{"-b",	FILBDEV},
+	{"-p",	FILFIFO},
+	{"-u",	FILSUID},
+	{"-g",	FILSGID},
+	{"-k",	FILSTCK},
+	{"-s",	FILGZ},
+	{"-t",	FILTT},
+	{"-z",	STREZ},
+	{"-n",	STRNZ},
+	{"-h",	FILSYM},		/* for backwards compat */
+	{"-O",	FILUID},
+	{"-G",	FILGID},
+	{"-L",	FILSYM},
+	{"-S",	FILSOCK},
+	{"=",	STREQ},
+	{"==",	STREQ},
+	{"!=",	STRNE},
+	{"<",	STRLT},
+	{">",	STRGT},
+	{"-eq",	INTEQ},
+	{"-ne",	INTNE},
+	{"-ge",	INTGE},
+	{"-gt",	INTGT},
+	{"-le",	INTLE},
+	{"-lt",	INTLT},
+	{"-nt",	FILNT},
+	{"-ot",	FILOT},
+	{"-ef",	FILEQ},
+	{"!",	UNOT},
+	{"-a",	BAND},
+	{"-o",	BOR},
+	{"(",	LPAREN},
+	{")",	RPAREN},
+	{"",	0}
+};
+
+static int nargc;
+static char **t_wp;
+static int parenlevel;
+
+static int	aexpr(enum token);
+static int	binop(enum token);
+static int	equalf(const char *, const char *);
+static int	filstat(char *, enum token);
+static int	getn(const char *);
+static intmax_t	getq(const char *);
+static int	intcmp(const char *, const char *);
+static int	isunopoperand(void);
+static int	islparenoperand(void);
+static int	isrparenoperand(void);
+static int	newerf(const char *, const char *);
+static int	nexpr(enum token);
+static int	oexpr(enum token);
+static int	olderf(const char *, const char *);
+static int	primary(enum token);
+static void	syntax(const char *, const char *);
+static enum	token t_lex(char *);
+
+int
+main(int argc, char **argv)
+{
+	int	res;
+	char	*p;
+
+	if ((p = strrchr(argv[0], '/')) == NULL)
+		p = argv[0];
+	else
+		p++;
+	if (strcmp(p, "[") == 0) {
+		if (strcmp(argv[--argc], "]") != 0)
+			error("missing ]");
+		argv[argc] = NULL;
+	}
+
+	/* no expression => false */
+	if (--argc <= 0)
+		return 1;
+
+#ifndef SHELL
+	(void)setlocale(LC_CTYPE, "");
+#endif
+	nargc = argc;
+	t_wp = &argv[1];
+	parenlevel = 0;
+	if (nargc == 4 && strcmp(*t_wp, "!") == 0) {
+		/* Things like ! "" -o x do not fit in the normal grammar. */
+		--nargc;
+		++t_wp;
+		res = oexpr(t_lex(*t_wp));
+	} else
+		res = !oexpr(t_lex(*t_wp));
+
+	if (--nargc > 0)
+		syntax(*t_wp, "unexpected operator");
+
+	return res;
+}
+
+static void
+syntax(const char *op, const char *msg)
+{
+
+	if (op && *op)
+		error("%s: %s", op, msg);
+	else
+		error("%s", msg);
+}
+
+static int
+oexpr(enum token n)
+{
+	int res;
+
+	res = aexpr(n);
+	if (t_lex(nargc > 0 ? (--nargc, *++t_wp) : NULL) == BOR)
+		return oexpr(t_lex(nargc > 0 ? (--nargc, *++t_wp) : NULL)) ||
+		    res;
+	t_wp--;
+	nargc++;
+	return res;
+}
+
+static int
+aexpr(enum token n)
+{
+	int res;
+
+	res = nexpr(n);
+	if (t_lex(nargc > 0 ? (--nargc, *++t_wp) : NULL) == BAND)
+		return aexpr(t_lex(nargc > 0 ? (--nargc, *++t_wp) : NULL)) &&
+		    res;
+	t_wp--;
+	nargc++;
+	return res;
+}
+
+static int
+nexpr(enum token n)
+{
+	if (n == UNOT)
+		return !nexpr(t_lex(nargc > 0 ? (--nargc, *++t_wp) : NULL));
+	return primary(n);
+}
+
+static int
+primary(enum token n)
+{
+	enum token nn;
+	int res;
+
+	if (n == EOI)
+		return 0;		/* missing expression */
+	if (n == LPAREN) {
+		parenlevel++;
+		if ((nn = t_lex(nargc > 0 ? (--nargc, *++t_wp) : NULL)) ==
+		    RPAREN) {
+			parenlevel--;
+			return 0;	/* missing expression */
+		}
+		res = oexpr(nn);
+		if (t_lex(nargc > 0 ? (--nargc, *++t_wp) : NULL) != RPAREN)
+			syntax(NULL, "closing paren expected");
+		parenlevel--;
+		return res;
+	}
+	if (TOKEN_TYPE(n) == UNOP) {
+		/* unary expression */
+		if (--nargc == 0)
+			syntax(NULL, "argument expected"); /* impossible */
+		switch (n) {
+		case STREZ:
+			return strlen(*++t_wp) == 0;
+		case STRNZ:
+			return strlen(*++t_wp) != 0;
+		case FILTT:
+			return isatty(getn(*++t_wp));
+		default:
+			return filstat(*++t_wp, n);
+		}
+	}
+
+	nn = t_lex(nargc > 0 ? t_wp[1] : NULL);
+	if (TOKEN_TYPE(nn) == BINOP)
+		return binop(nn);
+
+	return strlen(*t_wp) > 0;
+}
+
+static int
+binop(enum token n)
+{
+	const char *opnd1, *op, *opnd2;
+
+	opnd1 = *t_wp;
+	op = nargc > 0 ? (--nargc, *++t_wp) : NULL;
+
+	if ((opnd2 = nargc > 0 ? (--nargc, *++t_wp) : NULL) == NULL)
+		syntax(op, "argument expected");
+
+	switch (n) {
+	case STREQ:
+		return strcmp(opnd1, opnd2) == 0;
+	case STRNE:
+		return strcmp(opnd1, opnd2) != 0;
+	case STRLT:
+		return strcmp(opnd1, opnd2) < 0;
+	case STRGT:
+		return strcmp(opnd1, opnd2) > 0;
+	case INTEQ:
+		return intcmp(opnd1, opnd2) == 0;
+	case INTNE:
+		return intcmp(opnd1, opnd2) != 0;
+	case INTGE:
+		return intcmp(opnd1, opnd2) >= 0;
+	case INTGT:
+		return intcmp(opnd1, opnd2) > 0;
+	case INTLE:
+		return intcmp(opnd1, opnd2) <= 0;
+	case INTLT:
+		return intcmp(opnd1, opnd2) < 0;
+	case FILNT:
+		return newerf (opnd1, opnd2);
+	case FILOT:
+		return olderf (opnd1, opnd2);
+	case FILEQ:
+		return equalf (opnd1, opnd2);
+	default:
+		abort();
+		/* NOTREACHED */
+	}
+}
+
+static int
+filstat(char *nm, enum token mode)
+{
+	struct stat s;
+
+	if (mode == FILSYM ? lstat(nm, &s) : stat(nm, &s))
+		return 0;
+
+	switch (mode) {
+	case FILRD:
+		return (eaccess(nm, R_OK) == 0);
+	case FILWR:
+		return (eaccess(nm, W_OK) == 0);
+	case FILEX:
+		/* XXX work around eaccess(2) false positives for superuser */
+		if (eaccess(nm, X_OK) != 0)
+			return 0;
+		if (S_ISDIR(s.st_mode) || geteuid() != 0)
+			return 1;
+		return (s.st_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) != 0;
+	case FILEXIST:
+		return (eaccess(nm, F_OK) == 0);
+	case FILREG:
+		return S_ISREG(s.st_mode);
+	case FILDIR:
+		return S_ISDIR(s.st_mode);
+	case FILCDEV:
+		return S_ISCHR(s.st_mode);
+	case FILBDEV:
+		return S_ISBLK(s.st_mode);
+	case FILFIFO:
+		return S_ISFIFO(s.st_mode);
+	case FILSOCK:
+		return S_ISSOCK(s.st_mode);
+	case FILSYM:
+		return S_ISLNK(s.st_mode);
+	case FILSUID:
+		return (s.st_mode & S_ISUID) != 0;
+	case FILSGID:
+		return (s.st_mode & S_ISGID) != 0;
+	case FILSTCK:
+		return (s.st_mode & S_ISVTX) != 0;
+	case FILGZ:
+		return s.st_size > (off_t)0;
+	case FILUID:
+		return s.st_uid == geteuid();
+	case FILGID:
+		return s.st_gid == getegid();
+	default:
+		return 1;
+	}
+}
+
+static enum token
+t_lex(char *s)
+{
+	struct t_op const *op = ops;
+
+	if (s == 0) {
+		return EOI;
+	}
+	while (*op->op_text) {
+		if (strcmp(s, op->op_text) == 0) {
+			if (((TOKEN_TYPE(op->op_num) == UNOP ||
+			    TOKEN_TYPE(op->op_num) == BUNOP)
+						&& isunopoperand()) ||
+			    (op->op_num == LPAREN && islparenoperand()) ||
+			    (op->op_num == RPAREN && isrparenoperand()))
+				break;
+			return op->op_num;
+		}
+		op++;
+	}
+	return OPERAND;
+}
+
+static int
+isunopoperand(void)
+{
+	struct t_op const *op = ops;
+	char *s;
+	char *t;
+
+	if (nargc == 1)
+		return 1;
+	s = *(t_wp + 1);
+	if (nargc == 2)
+		return parenlevel == 1 && strcmp(s, ")") == 0;
+	t = *(t_wp + 2);
+	while (*op->op_text) {
+		if (strcmp(s, op->op_text) == 0)
+			return TOKEN_TYPE(op->op_num) == BINOP &&
+			    (parenlevel == 0 || t[0] != ')' || t[1] != '\0');
+		op++;
+	}
+	return 0;
+}
+
+static int
+islparenoperand(void)
+{
+	struct t_op const *op = ops;
+	char *s;
+
+	if (nargc == 1)
+		return 1;
+	s = *(t_wp + 1);
+	if (nargc == 2)
+		return parenlevel == 1 && strcmp(s, ")") == 0;
+	if (nargc != 3)
+		return 0;
+	while (*op->op_text) {
+		if (strcmp(s, op->op_text) == 0)
+			return TOKEN_TYPE(op->op_num) == BINOP;
+		op++;
+	}
+	return 0;
+}
+
+static int
+isrparenoperand(void)
+{
+	char *s;
+
+	if (nargc == 1)
+		return 0;
+	s = *(t_wp + 1);
+	if (nargc == 2)
+		return parenlevel == 1 && strcmp(s, ")") == 0;
+	return 0;
+}
+
+/* atoi with error detection */
+static int
+getn(const char *s)
+{
+	char *p;
+	long r;
+
+	errno = 0;
+	r = strtol(s, &p, 10);
+
+	if (s == p)
+		error("%s: bad number", s);
+
+	if (errno != 0)
+		error((errno == EINVAL) ? "%s: bad number" :
+					  "%s: out of range", s);
+
+	while (isspace((unsigned char)*p))
+		p++;
+
+	if (*p)
+		error("%s: bad number", s);
+
+	return (int) r;
+}
+
+/* atoi with error detection and 64 bit range */
+static intmax_t
+getq(const char *s)
+{
+	char *p;
+	intmax_t r;
+
+	errno = 0;
+	r = strtoimax(s, &p, 10);
+
+	if (s == p)
+		error("%s: bad number", s);
+
+	if (errno != 0)
+		error((errno == EINVAL) ? "%s: bad number" :
+					  "%s: out of range", s);
+
+	while (isspace((unsigned char)*p))
+		p++;
+
+	if (*p)
+		error("%s: bad number", s);
+
+	return r;
+}
+
+static int
+intcmp (const char *s1, const char *s2)
+{
+	intmax_t q1, q2;
+
+
+	q1 = getq(s1);
+	q2 = getq(s2);
+
+	if (q1 > q2)
+		return 1;
+
+	if (q1 < q2)
+		return -1;
+
+	return 0;
+}
+
+static int
+newerf (const char *f1, const char *f2)
+{
+	struct stat b1, b2;
+
+	if (stat(f1, &b1) != 0 || stat(f2, &b2) != 0)
+		return 0;
+
+	if (b1.st_mtim.tv_sec > b2.st_mtim.tv_sec)
+		return 1;
+	if (b1.st_mtim.tv_sec < b2.st_mtim.tv_sec)
+		return 0;
+
+       return (b1.st_mtim.tv_nsec > b2.st_mtim.tv_nsec);
+}
+
+static int
+olderf (const char *f1, const char *f2)
+{
+	return (newerf(f2, f1));
+}
+
+static int
+equalf (const char *f1, const char *f2)
+{
+	struct stat b1, b2;
+
+	return (stat (f1, &b1) == 0 &&
+		stat (f2, &b2) == 0 &&
+		b1.st_dev == b2.st_dev &&
+		b1.st_ino == b2.st_ino);
+}
diff --git a/external/sh/token.h b/external/sh/token.h
new file mode 100644
index 00000000..205dfe8d
--- /dev/null
+++ b/external/sh/token.h
@@ -0,0 +1,112 @@
+#define TEOF 0
+#define TNL 1
+#define TSEMI 2
+#define TBACKGND 3
+#define TAND 4
+#define TOR 5
+#define TPIPE 6
+#define TLP 7
+#define TRP 8
+#define TENDCASE 9
+#define TFALLTHRU 10
+#define TREDIR 11
+#define TWORD 12
+#define TIF 13
+#define TTHEN 14
+#define TELSE 15
+#define TELIF 16
+#define TFI 17
+#define TWHILE 18
+#define TUNTIL 19
+#define TFOR 20
+#define TDO 21
+#define TDONE 22
+#define TBEGIN 23
+#define TEND 24
+#define TCASE 25
+#define TESAC 26
+#define TNOT 27
+
+/* Array indicating which tokens mark the end of a list */
+static const char tokendlist[] = {
+	1,
+	0,
+	0,
+	0,
+	0,
+	0,
+	0,
+	0,
+	1,
+	1,
+	1,
+	0,
+	0,
+	0,
+	1,
+	1,
+	1,
+	1,
+	0,
+	0,
+	0,
+	1,
+	1,
+	0,
+	1,
+	0,
+	1,
+	0,
+};
+
+static const char *const tokname[] = {
+	"end of file",
+	"newline",
+	"\";\"",
+	"\"&\"",
+	"\"&&\"",
+	"\"||\"",
+	"\"|\"",
+	"\"(\"",
+	"\")\"",
+	"\";;\"",
+	"\";&\"",
+	"redirection",
+	"word",
+	"\"if\"",
+	"\"then\"",
+	"\"else\"",
+	"\"elif\"",
+	"\"fi\"",
+	"\"while\"",
+	"\"until\"",
+	"\"for\"",
+	"\"do\"",
+	"\"done\"",
+	"\"{\"",
+	"\"}\"",
+	"\"case\"",
+	"\"esac\"",
+	"\"!\"",
+};
+
+#define KWDOFFSET 13
+
+const char *const parsekwd[] = {
+	"if",
+	"then",
+	"else",
+	"elif",
+	"fi",
+	"while",
+	"until",
+	"for",
+	"do",
+	"done",
+	"{",
+	"}",
+	"case",
+	"esac",
+	"!",
+	0
+};
diff --git a/external/sh/trap.c b/external/sh/trap.c
new file mode 100644
index 00000000..a5a9c6b2
--- /dev/null
+++ b/external/sh/trap.c
@@ -0,0 +1,551 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)trap.c	8.5 (Berkeley) 6/5/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: head/bin/sh/trap.c 281718 2015-04-18 23:49:57Z bdrewery $");
+
+#include <signal.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+#include "shell.h"
+#include "main.h"
+#include "nodes.h"	/* for other headers */
+#include "eval.h"
+#include "jobs.h"
+#include "show.h"
+#include "options.h"
+#include "syntax.h"
+#include "output.h"
+#include "memalloc.h"
+#include "error.h"
+#include "trap.h"
+#include "mystring.h"
+#include "builtins.h"
+#include "myhistedit.h"
+
+
+/*
+ * Sigmode records the current value of the signal handlers for the various
+ * modes.  A value of zero means that the current handler is not known.
+ * S_HARD_IGN indicates that the signal was ignored on entry to the shell,
+ */
+
+#define S_DFL 1			/* default signal handling (SIG_DFL) */
+#define S_CATCH 2		/* signal is caught */
+#define S_IGN 3			/* signal is ignored (SIG_IGN) */
+#define S_HARD_IGN 4		/* signal is ignored permanently */
+#define S_RESET 5		/* temporary - to reset a hard ignored sig */
+
+
+static char sigmode[NSIG];	/* current value of signal */
+volatile sig_atomic_t pendingsig;	/* indicates some signal received */
+volatile sig_atomic_t pendingsig_waitcmd;	/* indicates wait builtin should be interrupted */
+static int in_dotrap;			/* do we execute in a trap handler? */
+static char *volatile trap[NSIG];	/* trap handler commands */
+static volatile sig_atomic_t gotsig[NSIG];
+				/* indicates specified signal received */
+static int ignore_sigchld;	/* Used while handling SIGCHLD traps. */
+static int last_trapsig;
+
+static int exiting;		/* exitshell() has been called */
+static int exiting_exitstatus;	/* value passed to exitshell() */
+
+static int getsigaction(int, sig_t *);
+
+
+/*
+ * Map a string to a signal number.
+ *
+ * Note: the signal number may exceed NSIG.
+ */
+static int
+sigstring_to_signum(char *sig)
+{
+
+	if (is_number(sig)) {
+		int signo;
+
+		signo = atoi(sig);
+		return ((signo >= 0 && signo < NSIG) ? signo : (-1));
+	} else if (strcasecmp(sig, "EXIT") == 0) {
+		return (0);
+	} else {
+		int n;
+
+		if (strncasecmp(sig, "SIG", 3) == 0)
+			sig += 3;
+		for (n = 1; n < sys_nsig; n++)
+			if (sys_signame[n] &&
+			    strcasecmp(sys_signame[n], sig) == 0)
+				return (n);
+	}
+	return (-1);
+}
+
+
+/*
+ * Print a list of valid signal names.
+ */
+static void
+printsignals(void)
+{
+	int n, outlen;
+
+	outlen = 0;
+	for (n = 1; n < sys_nsig; n++) {
+		if (sys_signame[n]) {
+			out1fmt("%s", sys_signame[n]);
+			outlen += strlen(sys_signame[n]);
+		} else {
+			out1fmt("%d", n);
+			outlen += 3;	/* good enough */
+		}
+		++outlen;
+		if (outlen > 71 || n == sys_nsig - 1) {
+			out1str("\n");
+			outlen = 0;
+		} else {
+			out1c(' ');
+		}
+	}
+}
+
+
+/*
+ * The trap builtin.
+ */
+int
+trapcmd(int argc __unused, char **argv)
+{
+	char *action;
+	int signo;
+	int errors = 0;
+	int i;
+
+	while ((i = nextopt("l")) != '\0') {
+		switch (i) {
+		case 'l':
+			printsignals();
+			return (0);
+		}
+	}
+	argv = argptr;
+
+	if (*argv == NULL) {
+		for (signo = 0 ; signo < sys_nsig ; signo++) {
+			if (signo < NSIG && trap[signo] != NULL) {
+				out1str("trap -- ");
+				out1qstr(trap[signo]);
+				if (signo == 0) {
+					out1str(" EXIT\n");
+				} else if (sys_signame[signo]) {
+					out1fmt(" %s\n", sys_signame[signo]);
+				} else {
+					out1fmt(" %d\n", signo);
+				}
+			}
+		}
+		return 0;
+	}
+	action = NULL;
+	if (*argv && !is_number(*argv)) {
+		if (strcmp(*argv, "-") == 0)
+			argv++;
+		else {
+			action = *argv;
+			argv++;
+		}
+	}
+	for (; *argv; argv++) {
+		if ((signo = sigstring_to_signum(*argv)) == -1) {
+			warning("bad signal %s", *argv);
+			errors = 1;
+			continue;
+		}
+		INTOFF;
+		if (action)
+			action = savestr(action);
+		if (trap[signo])
+			ckfree(trap[signo]);
+		trap[signo] = action;
+		if (signo != 0)
+			setsignal(signo);
+		INTON;
+	}
+	return errors;
+}
+
+
+/*
+ * Clear traps on a fork.
+ */
+void
+clear_traps(void)
+{
+	char *volatile *tp;
+
+	for (tp = trap ; tp <= &trap[NSIG - 1] ; tp++) {
+		if (*tp && **tp) {	/* trap not NULL or SIG_IGN */
+			INTOFF;
+			ckfree(*tp);
+			*tp = NULL;
+			if (tp != &trap[0])
+				setsignal(tp - trap);
+			INTON;
+		}
+	}
+}
+
+
+/*
+ * Check if we have any traps enabled.
+ */
+int
+have_traps(void)
+{
+	char *volatile *tp;
+
+	for (tp = trap ; tp <= &trap[NSIG - 1] ; tp++) {
+		if (*tp && **tp)	/* trap not NULL or SIG_IGN */
+			return 1;
+	}
+	return 0;
+}
+
+/*
+ * Set the signal handler for the specified signal.  The routine figures
+ * out what it should be set to.
+ */
+void
+setsignal(int signo)
+{
+	int action;
+	sig_t sigact = SIG_DFL;
+	struct sigaction sa;
+	char *t;
+
+	if ((t = trap[signo]) == NULL)
+		action = S_DFL;
+	else if (*t != '\0')
+		action = S_CATCH;
+	else
+		action = S_IGN;
+	if (action == S_DFL) {
+		switch (signo) {
+		case SIGINT:
+			action = S_CATCH;
+			break;
+		case SIGQUIT:
+#ifdef DEBUG
+			{
+			extern int debug;
+
+			if (debug)
+				break;
+			}
+#endif
+			action = S_CATCH;
+			break;
+		case SIGTERM:
+			if (rootshell && iflag)
+				action = S_IGN;
+			break;
+#if JOBS
+		case SIGTSTP:
+		case SIGTTOU:
+			if (rootshell && mflag)
+				action = S_IGN;
+			break;
+#endif
+		}
+	}
+
+	t = &sigmode[signo];
+	if (*t == 0) {
+		/*
+		 * current setting unknown
+		 */
+		if (!getsigaction(signo, &sigact)) {
+			/*
+			 * Pretend it worked; maybe we should give a warning
+			 * here, but other shells don't. We don't alter
+			 * sigmode, so that we retry every time.
+			 */
+			return;
+		}
+		if (sigact == SIG_IGN) {
+			if (mflag && (signo == SIGTSTP ||
+			     signo == SIGTTIN || signo == SIGTTOU)) {
+				*t = S_IGN;	/* don't hard ignore these */
+			} else
+				*t = S_HARD_IGN;
+		} else {
+			*t = S_RESET;	/* force to be set */
+		}
+	}
+	if (*t == S_HARD_IGN || *t == action)
+		return;
+	switch (action) {
+		case S_DFL:	sigact = SIG_DFL;	break;
+		case S_CATCH:  	sigact = onsig;		break;
+		case S_IGN:	sigact = SIG_IGN;	break;
+	}
+	*t = action;
+	sa.sa_handler = sigact;
+	sa.sa_flags = 0;
+	sigemptyset(&sa.sa_mask);
+	sigaction(signo, &sa, NULL);
+}
+
+
+/*
+ * Return the current setting for sig w/o changing it.
+ */
+static int
+getsigaction(int signo, sig_t *sigact)
+{
+	struct sigaction sa;
+
+	if (sigaction(signo, (struct sigaction *)0, &sa) == -1)
+		return 0;
+	*sigact = (sig_t) sa.sa_handler;
+	return 1;
+}
+
+
+/*
+ * Ignore a signal.
+ */
+void
+ignoresig(int signo)
+{
+
+	if (sigmode[signo] == 0)
+		setsignal(signo);
+	if (sigmode[signo] != S_IGN && sigmode[signo] != S_HARD_IGN) {
+		signal(signo, SIG_IGN);
+		sigmode[signo] = S_IGN;
+	}
+}
+
+
+int
+issigchldtrapped(void)
+{
+
+	return (trap[SIGCHLD] != NULL && *trap[SIGCHLD] != '\0');
+}
+
+
+/*
+ * Signal handler.
+ */
+void
+onsig(int signo)
+{
+
+	if (signo == SIGINT && trap[SIGINT] == NULL) {
+		/*
+		 * The !in_dotrap here is safe.  The only way we can arrive
+		 * here with in_dotrap set is that a trap handler set SIGINT to
+		 * SIG_DFL and killed itself.
+		 */
+		if (suppressint && !in_dotrap)
+			SET_PENDING_INT;
+		else
+			onint();
+		return;
+	}
+
+	/* If we are currently in a wait builtin, prepare to break it */
+	if (signo == SIGINT || signo == SIGQUIT)
+		pendingsig_waitcmd = signo;
+
+	if (trap[signo] != NULL && trap[signo][0] != '\0' &&
+	    (signo != SIGCHLD || !ignore_sigchld)) {
+		gotsig[signo] = 1;
+		pendingsig = signo;
+		pendingsig_waitcmd = signo;
+	}
+}
+
+
+/*
+ * Called to execute a trap.  Perhaps we should avoid entering new trap
+ * handlers while we are executing a trap handler.
+ */
+void
+dotrap(void)
+{
+	int i;
+	int savestatus, prev_evalskip, prev_skipcount;
+
+	in_dotrap++;
+	for (;;) {
+		pendingsig = 0;
+		pendingsig_waitcmd = 0;
+		for (i = 1; i < NSIG; i++) {
+			if (gotsig[i]) {
+				gotsig[i] = 0;
+				if (trap[i]) {
+					/*
+					 * Ignore SIGCHLD to avoid infinite
+					 * recursion if the trap action does
+					 * a fork.
+					 */
+					if (i == SIGCHLD)
+						ignore_sigchld++;
+
+					/*
+					 * Backup current evalskip
+					 * state and reset it before
+					 * executing a trap, so that the
+					 * trap is not disturbed by an
+					 * ongoing break/continue/return
+					 * statement.
+					 */
+					prev_evalskip  = evalskip;
+					prev_skipcount = skipcount;
+					evalskip = 0;
+
+					last_trapsig = i;
+					savestatus = exitstatus;
+					evalstring(trap[i], 0);
+
+					/*
+					 * If such a command was not
+					 * already in progress, allow a
+					 * break/continue/return in the
+					 * trap action to have an effect
+					 * outside of it.
+					 */
+					if (evalskip == 0 ||
+					    prev_evalskip != 0) {
+						evalskip  = prev_evalskip;
+						skipcount = prev_skipcount;
+						exitstatus = savestatus;
+					}
+
+					if (i == SIGCHLD)
+						ignore_sigchld--;
+				}
+				break;
+			}
+		}
+		if (i >= NSIG)
+			break;
+	}
+	in_dotrap--;
+}
+
+
+/*
+ * Controls whether the shell is interactive or not.
+ */
+void
+setinteractive(int on)
+{
+	static int is_interactive = -1;
+
+	if (on == is_interactive)
+		return;
+	setsignal(SIGINT);
+	setsignal(SIGQUIT);
+	setsignal(SIGTERM);
+	is_interactive = on;
+}
+
+
+/*
+ * Called to exit the shell.
+ */
+void
+exitshell(int status)
+{
+	TRACE(("exitshell(%d) pid=%d\n", status, getpid()));
+	exiting = 1;
+	exiting_exitstatus = status;
+	exitshell_savedstatus();
+}
+
+void
+exitshell_savedstatus(void)
+{
+	struct jmploc loc1, loc2;
+	char *p;
+	int sig = 0;
+	sigset_t sigs;
+
+	if (!exiting) {
+		if (in_dotrap && last_trapsig) {
+			sig = last_trapsig;
+			exiting_exitstatus = sig + 128;
+		} else
+			exiting_exitstatus = oexitstatus;
+	}
+	exitstatus = oexitstatus = exiting_exitstatus;
+	if (!setjmp(loc1.loc)) {
+		handler = &loc1;
+		if ((p = trap[0]) != NULL && *p != '\0') {
+			/*
+			 * Reset evalskip, or the trap on EXIT could be
+			 * interrupted if the last command was a "return".
+			 */
+			evalskip = 0;
+			trap[0] = NULL;
+			evalstring(p, 0);
+		}
+	}
+	if (!setjmp(loc2.loc)) {
+		handler = &loc2;		/* probably unnecessary */
+		flushall();
+#if JOBS
+		setjobctl(0);
+#endif
+	}
+	if (sig != 0 && sig != SIGSTOP && sig != SIGTSTP && sig != SIGTTIN &&
+	    sig != SIGTTOU) {
+		signal(sig, SIG_DFL);
+		sigemptyset(&sigs);
+		sigaddset(&sigs, sig);
+		sigprocmask(SIG_UNBLOCK, &sigs, NULL);
+		kill(getpid(), sig);
+		/* If the default action is to ignore, fall back to _exit(). */
+	}
+	_exit(exiting_exitstatus);
+}
diff --git a/external/sh/trap.h b/external/sh/trap.h
new file mode 100644
index 00000000..a0006471
--- /dev/null
+++ b/external/sh/trap.h
@@ -0,0 +1,48 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)trap.h	8.3 (Berkeley) 6/5/95
+ * $FreeBSD: head/bin/sh/trap.h 276038 2014-12-21 23:09:59Z jilles $
+ */
+
+extern volatile sig_atomic_t pendingsig;
+extern volatile sig_atomic_t pendingsig_waitcmd;
+
+void clear_traps(void);
+int have_traps(void);
+void setsignal(int);
+void ignoresig(int);
+int issigchldtrapped(void);
+void onsig(int);
+void dotrap(void);
+void setinteractive(int);
+void exitshell(int) __dead2;
+void exitshell_savedstatus(void) __dead2;
diff --git a/external/sh/var.c b/external/sh/var.c
new file mode 100644
index 00000000..53933df8
--- /dev/null
+++ b/external/sh/var.c
@@ -0,0 +1,956 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)var.c	8.3 (Berkeley) 5/4/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: head/bin/sh/var.c 279569 2015-03-03 21:21:43Z jilles $");
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <paths.h>
+
+/*
+ * Shell variables.
+ */
+
+#include <locale.h>
+#include <langinfo.h>
+
+#include "shell.h"
+#include "output.h"
+#include "expand.h"
+#include "nodes.h"	/* for other headers */
+#include "eval.h"	/* defines cmdenviron */
+#include "exec.h"
+#include "syntax.h"
+#include "options.h"
+#include "mail.h"
+#include "var.h"
+#include "memalloc.h"
+#include "error.h"
+#include "mystring.h"
+#include "parser.h"
+#include "builtins.h"
+#ifndef NO_HISTORY
+#include "myhistedit.h"
+#endif
+
+
+#define VTABSIZE 39
+
+
+struct varinit {
+	struct var *var;
+	int flags;
+	const char *text;
+	void (*func)(const char *);
+};
+
+
+#ifndef NO_HISTORY
+struct var vhistsize;
+struct var vterm;
+#endif
+struct var vifs;
+struct var vmail;
+struct var vmpath;
+struct var vpath;
+struct var vps1;
+struct var vps2;
+struct var vps4;
+static struct var voptind;
+struct var vdisvfork;
+
+struct localvar *localvars;
+int forcelocal;
+
+static const struct varinit varinit[] = {
+#ifndef NO_HISTORY
+	{ &vhistsize,	VUNSET,				"HISTSIZE=",
+	  sethistsize },
+#endif
+	{ &vifs,	0,				"IFS= \t\n",
+	  NULL },
+	{ &vmail,	VUNSET,				"MAIL=",
+	  NULL },
+	{ &vmpath,	VUNSET,				"MAILPATH=",
+	  NULL },
+	{ &vpath,	0,				"PATH=" _PATH_DEFPATH,
+	  changepath },
+	/*
+	 * vps1 depends on uid
+	 */
+	{ &vps2,	0,				"PS2=> ",
+	  NULL },
+	{ &vps4,	0,				"PS4=+ ",
+	  NULL },
+#ifndef NO_HISTORY
+	{ &vterm,	VUNSET,				"TERM=",
+	  setterm },
+#endif
+	{ &voptind,	0,				"OPTIND=1",
+	  getoptsreset },
+	{ &vdisvfork,	VUNSET,				"SH_DISABLE_VFORK=",
+	  NULL },
+	{ NULL,	0,				NULL,
+	  NULL }
+};
+
+static struct var *vartab[VTABSIZE];
+
+static const char *const locale_names[7] = {
+	"LC_COLLATE", "LC_CTYPE", "LC_MONETARY",
+	"LC_NUMERIC", "LC_TIME", "LC_MESSAGES", NULL
+};
+static const int locale_categories[7] = {
+	LC_COLLATE, LC_CTYPE, LC_MONETARY, LC_NUMERIC, LC_TIME, LC_MESSAGES, 0
+};
+
+static int varequal(const char *, const char *);
+static struct var *find_var(const char *, struct var ***, int *);
+static int localevar(const char *);
+static void setvareq_const(const char *s, int flags);
+
+extern char **environ;
+
+/*
+ * This routine initializes the builtin variables and imports the environment.
+ * It is called when the shell is initialized.
+ */
+
+void
+initvar(void)
+{
+	char ppid[20];
+	const struct varinit *ip;
+	struct var *vp;
+	struct var **vpp;
+	char **envp;
+
+	for (ip = varinit ; (vp = ip->var) != NULL ; ip++) {
+		if (find_var(ip->text, &vpp, &vp->name_len) != NULL)
+			continue;
+		vp->next = *vpp;
+		*vpp = vp;
+		vp->text = __DECONST(char *, ip->text);
+		vp->flags = ip->flags | VSTRFIXED | VTEXTFIXED;
+		vp->func = ip->func;
+	}
+	/*
+	 * PS1 depends on uid
+	 */
+	if (find_var("PS1", &vpp, &vps1.name_len) == NULL) {
+		vps1.next = *vpp;
+		*vpp = &vps1;
+		vps1.text = __DECONST(char *, geteuid() ? "PS1=$ " : "PS1=# ");
+		vps1.flags = VSTRFIXED|VTEXTFIXED;
+	}
+	fmtstr(ppid, sizeof(ppid), "%d", (int)getppid());
+	setvarsafe("PPID", ppid, 0);
+	for (envp = environ ; *envp ; envp++) {
+		if (strchr(*envp, '=')) {
+			setvareq(*envp, VEXPORT|VTEXTFIXED);
+		}
+	}
+	setvareq_const("OPTIND=1", 0);
+}
+
+/*
+ * Safe version of setvar, returns 1 on success 0 on failure.
+ */
+
+int
+setvarsafe(const char *name, const char *val, int flags)
+{
+	struct jmploc jmploc;
+	struct jmploc *const savehandler = handler;
+	int err = 0;
+	int inton;
+
+	inton = is_int_on();
+	if (setjmp(jmploc.loc))
+		err = 1;
+	else {
+		handler = &jmploc;
+		setvar(name, val, flags);
+	}
+	handler = savehandler;
+	SETINTON(inton);
+	return err;
+}
+
+/*
+ * Set the value of a variable.  The flags argument is stored with the
+ * flags of the variable.  If val is NULL, the variable is unset.
+ */
+
+void
+setvar(const char *name, const char *val, int flags)
+{
+	const char *p;
+	size_t len;
+	size_t namelen;
+	size_t vallen;
+	char *nameeq;
+	int isbad;
+
+	isbad = 0;
+	p = name;
+	if (! is_name(*p))
+		isbad = 1;
+	p++;
+	for (;;) {
+		if (! is_in_name(*p)) {
+			if (*p == '\0' || *p == '=')
+				break;
+			isbad = 1;
+		}
+		p++;
+	}
+	namelen = p - name;
+	if (isbad)
+		error("%.*s: bad variable name", (int)namelen, name);
+	len = namelen + 2;		/* 2 is space for '=' and '\0' */
+	if (val == NULL) {
+		flags |= VUNSET;
+		vallen = 0;
+	} else {
+		vallen = strlen(val);
+		len += vallen;
+	}
+	INTOFF;
+	nameeq = ckmalloc(len);
+	memcpy(nameeq, name, namelen);
+	nameeq[namelen] = '=';
+	if (val)
+		memcpy(nameeq + namelen + 1, val, vallen + 1);
+	else
+		nameeq[namelen + 1] = '\0';
+	setvareq(nameeq, flags);
+	INTON;
+}
+
+static int
+localevar(const char *s)
+{
+	const char *const *ss;
+
+	if (*s != 'L')
+		return 0;
+	if (varequal(s + 1, "ANG"))
+		return 1;
+	if (strncmp(s + 1, "C_", 2) != 0)
+		return 0;
+	if (varequal(s + 3, "ALL"))
+		return 1;
+	for (ss = locale_names; *ss ; ss++)
+		if (varequal(s + 3, *ss + 3))
+			return 1;
+	return 0;
+}
+
+
+/*
+ * Sets/unsets an environment variable from a pointer that may actually be a
+ * pointer into environ where the string should not be manipulated.
+ */
+static void
+change_env(const char *s, int set)
+{
+	char *eqp;
+	char *ss;
+
+	INTOFF;
+	ss = savestr(s);
+	if ((eqp = strchr(ss, '=')) != NULL)
+		*eqp = '\0';
+	if (set && eqp != NULL)
+		(void) setenv(ss, eqp + 1, 1);
+	else
+		(void) unsetenv(ss);
+	ckfree(ss);
+	INTON;
+
+	return;
+}
+
+
+/*
+ * Same as setvar except that the variable and value are passed in
+ * the first argument as name=value.  Since the first argument will
+ * be actually stored in the table, it should not be a string that
+ * will go away.
+ */
+
+void
+setvareq(char *s, int flags)
+{
+	struct var *vp, **vpp;
+	int nlen;
+
+	if (aflag)
+		flags |= VEXPORT;
+	if (forcelocal && !(flags & (VNOSET | VNOLOCAL)))
+		mklocal(s);
+	vp = find_var(s, &vpp, &nlen);
+	if (vp != NULL) {
+		if (vp->flags & VREADONLY) {
+			if ((flags & (VTEXTFIXED|VSTACK)) == 0)
+				ckfree(s);
+			error("%.*s: is read only", vp->name_len, s);
+		}
+		if (flags & VNOSET) {
+			if ((flags & (VTEXTFIXED|VSTACK)) == 0)
+				ckfree(s);
+			return;
+		}
+		INTOFF;
+
+		if (vp->func && (flags & VNOFUNC) == 0)
+			(*vp->func)(s + vp->name_len + 1);
+
+		if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
+			ckfree(vp->text);
+
+		vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET);
+		vp->flags |= flags;
+		vp->text = s;
+
+		/*
+		 * We could roll this to a function, to handle it as
+		 * a regular variable function callback, but why bother?
+		 *
+		 * Note: this assumes iflag is not set to 1 initially.
+		 * As part of initvar(), this is called before arguments
+		 * are looked at.
+		 */
+		if ((vp == &vmpath || (vp == &vmail && ! mpathset())) &&
+		    iflag == 1)
+			chkmail(1);
+		if ((vp->flags & VEXPORT) && localevar(s)) {
+			change_env(s, 1);
+			(void) setlocale(LC_ALL, "");
+			updatecharset();
+		}
+		INTON;
+		return;
+	}
+	/* not found */
+	if (flags & VNOSET) {
+		if ((flags & (VTEXTFIXED|VSTACK)) == 0)
+			ckfree(s);
+		return;
+	}
+	INTOFF;
+	vp = ckmalloc(sizeof (*vp));
+	vp->flags = flags;
+	vp->text = s;
+	vp->name_len = nlen;
+	vp->next = *vpp;
+	vp->func = NULL;
+	*vpp = vp;
+	if ((vp->flags & VEXPORT) && localevar(s)) {
+		change_env(s, 1);
+		(void) setlocale(LC_ALL, "");
+		updatecharset();
+	}
+	INTON;
+}
+
+
+static void
+setvareq_const(const char *s, int flags)
+{
+	setvareq(__DECONST(char *, s), flags | VTEXTFIXED);
+}
+
+
+/*
+ * Process a linked list of variable assignments.
+ */
+
+void
+listsetvar(struct strlist *list, int flags)
+{
+	struct strlist *lp;
+
+	INTOFF;
+	for (lp = list ; lp ; lp = lp->next) {
+		setvareq(savestr(lp->text), flags);
+	}
+	INTON;
+}
+
+
+
+/*
+ * Find the value of a variable.  Returns NULL if not set.
+ */
+
+char *
+lookupvar(const char *name)
+{
+	struct var *v;
+
+	v = find_var(name, NULL, NULL);
+	if (v == NULL || v->flags & VUNSET)
+		return NULL;
+	return v->text + v->name_len + 1;
+}
+
+
+
+/*
+ * Search the environment of a builtin command.  If the second argument
+ * is nonzero, return the value of a variable even if it hasn't been
+ * exported.
+ */
+
+char *
+bltinlookup(const char *name, int doall)
+{
+	struct strlist *sp;
+	struct var *v;
+	char *result;
+
+	result = NULL;
+	for (sp = cmdenviron ; sp ; sp = sp->next) {
+		if (varequal(sp->text, name))
+			result = strchr(sp->text, '=') + 1;
+	}
+	if (result != NULL)
+		return result;
+
+	v = find_var(name, NULL, NULL);
+	if (v == NULL || v->flags & VUNSET ||
+	    (!doall && (v->flags & VEXPORT) == 0))
+		return NULL;
+	return v->text + v->name_len + 1;
+}
+
+
+/*
+ * Set up locale for a builtin (LANG/LC_* assignments).
+ */
+void
+bltinsetlocale(void)
+{
+	struct strlist *lp;
+	int act = 0;
+	char *loc, *locdef;
+	int i;
+
+	for (lp = cmdenviron ; lp ; lp = lp->next) {
+		if (localevar(lp->text)) {
+			act = 1;
+			break;
+		}
+	}
+	if (!act)
+		return;
+	loc = bltinlookup("LC_ALL", 0);
+	INTOFF;
+	if (loc != NULL) {
+		setlocale(LC_ALL, loc);
+		INTON;
+		updatecharset();
+		return;
+	}
+	locdef = bltinlookup("LANG", 0);
+	for (i = 0; locale_names[i] != NULL; i++) {
+		loc = bltinlookup(locale_names[i], 0);
+		if (loc == NULL)
+			loc = locdef;
+		if (loc != NULL)
+			setlocale(locale_categories[i], loc);
+	}
+	INTON;
+	updatecharset();
+}
+
+/*
+ * Undo the effect of bltinlocaleset().
+ */
+void
+bltinunsetlocale(void)
+{
+	struct strlist *lp;
+
+	INTOFF;
+	for (lp = cmdenviron ; lp ; lp = lp->next) {
+		if (localevar(lp->text)) {
+			setlocale(LC_ALL, "");
+			updatecharset();
+			return;
+		}
+	}
+	INTON;
+}
+
+/*
+ * Update the localeisutf8 flag.
+ */
+void
+updatecharset(void)
+{
+	char *charset;
+
+	charset = nl_langinfo(CODESET);
+	localeisutf8 = !strcmp(charset, "UTF-8");
+}
+
+void
+initcharset(void)
+{
+	updatecharset();
+	initial_localeisutf8 = localeisutf8;
+}
+
+/*
+ * Generate a list of exported variables.  This routine is used to construct
+ * the third argument to execve when executing a program.
+ */
+
+char **
+environment(void)
+{
+	int nenv;
+	struct var **vpp;
+	struct var *vp;
+	char **env, **ep;
+
+	nenv = 0;
+	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
+		for (vp = *vpp ; vp ; vp = vp->next)
+			if (vp->flags & VEXPORT)
+				nenv++;
+	}
+	ep = env = stalloc((nenv + 1) * sizeof *env);
+	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
+		for (vp = *vpp ; vp ; vp = vp->next)
+			if (vp->flags & VEXPORT)
+				*ep++ = vp->text;
+	}
+	*ep = NULL;
+	return env;
+}
+
+
+static int
+var_compare(const void *a, const void *b)
+{
+	const char *const *sa, *const *sb;
+
+	sa = a;
+	sb = b;
+	/*
+	 * This compares two var=value strings which creates a different
+	 * order from what you would probably expect.  POSIX is somewhat
+	 * ambiguous on what should be sorted exactly.
+	 */
+	return strcoll(*sa, *sb);
+}
+
+
+/*
+ * Command to list all variables which are set.  This is invoked from the
+ * set command when it is called without any options or operands.
+ */
+
+int
+showvarscmd(int argc __unused, char **argv __unused)
+{
+	struct var **vpp;
+	struct var *vp;
+	const char *s;
+	const char **vars;
+	int i, n;
+
+	/*
+	 * POSIX requires us to sort the variables.
+	 */
+	n = 0;
+	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
+		for (vp = *vpp; vp; vp = vp->next) {
+			if (!(vp->flags & VUNSET))
+				n++;
+		}
+	}
+
+	INTOFF;
+	vars = ckmalloc(n * sizeof(*vars));
+	i = 0;
+	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
+		for (vp = *vpp; vp; vp = vp->next) {
+			if (!(vp->flags & VUNSET))
+				vars[i++] = vp->text;
+		}
+	}
+
+	qsort(vars, n, sizeof(*vars), var_compare);
+	for (i = 0; i < n; i++) {
+		/*
+		 * Skip improper variable names so the output remains usable as
+		 * shell input.
+		 */
+		if (!isassignment(vars[i]))
+			continue;
+		s = strchr(vars[i], '=');
+		s++;
+		outbin(vars[i], s - vars[i], out1);
+		out1qstr(s);
+		out1c('\n');
+	}
+	ckfree(vars);
+	INTON;
+
+	return 0;
+}
+
+
+
+/*
+ * The export and readonly commands.
+ */
+
+int
+exportcmd(int argc __unused, char **argv)
+{
+	struct var **vpp;
+	struct var *vp;
+	char **ap;
+	char *name;
+	char *p;
+	char *cmdname;
+	int ch, values;
+	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
+
+	cmdname = argv[0];
+	values = 0;
+	while ((ch = nextopt("p")) != '\0') {
+		switch (ch) {
+		case 'p':
+			values = 1;
+			break;
+		}
+	}
+
+	if (values && *argptr != NULL)
+		error("-p requires no arguments");
+	if (*argptr != NULL) {
+		for (ap = argptr; (name = *ap) != NULL; ap++) {
+			if ((p = strchr(name, '=')) != NULL) {
+				p++;
+			} else {
+				vp = find_var(name, NULL, NULL);
+				if (vp != NULL) {
+					vp->flags |= flag;
+					if ((vp->flags & VEXPORT) && localevar(vp->text)) {
+						change_env(vp->text, 1);
+						(void) setlocale(LC_ALL, "");
+						updatecharset();
+					}
+					continue;
+				}
+			}
+			setvar(name, p, flag);
+		}
+	} else {
+		for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
+			for (vp = *vpp ; vp ; vp = vp->next) {
+				if (vp->flags & flag) {
+					if (values) {
+						/*
+						 * Skip improper variable names
+						 * so the output remains usable
+						 * as shell input.
+						 */
+						if (!isassignment(vp->text))
+							continue;
+						out1str(cmdname);
+						out1c(' ');
+					}
+					if (values && !(vp->flags & VUNSET)) {
+						outbin(vp->text,
+						    vp->name_len + 1, out1);
+						out1qstr(vp->text +
+						    vp->name_len + 1);
+					} else
+						outbin(vp->text, vp->name_len,
+						    out1);
+					out1c('\n');
+				}
+			}
+		}
+	}
+	return 0;
+}
+
+
+/*
+ * The "local" command.
+ */
+
+int
+localcmd(int argc __unused, char **argv __unused)
+{
+	char *name;
+
+	nextopt("");
+	if (! in_function())
+		error("Not in a function");
+	while ((name = *argptr++) != NULL) {
+		mklocal(name);
+	}
+	return 0;
+}
+
+
+/*
+ * Make a variable a local variable.  When a variable is made local, it's
+ * value and flags are saved in a localvar structure.  The saved values
+ * will be restored when the shell function returns.  We handle the name
+ * "-" as a special case.
+ */
+
+void
+mklocal(char *name)
+{
+	struct localvar *lvp;
+	struct var **vpp;
+	struct var *vp;
+
+	INTOFF;
+	lvp = ckmalloc(sizeof (struct localvar));
+	if (name[0] == '-' && name[1] == '\0') {
+		lvp->text = ckmalloc(sizeof optlist);
+		memcpy(lvp->text, optlist, sizeof optlist);
+		vp = NULL;
+	} else {
+		vp = find_var(name, &vpp, NULL);
+		if (vp == NULL) {
+			if (strchr(name, '='))
+				setvareq(savestr(name), VSTRFIXED | VNOLOCAL);
+			else
+				setvar(name, NULL, VSTRFIXED | VNOLOCAL);
+			vp = *vpp;	/* the new variable */
+			lvp->text = NULL;
+			lvp->flags = VUNSET;
+		} else {
+			lvp->text = vp->text;
+			lvp->flags = vp->flags;
+			vp->flags |= VSTRFIXED|VTEXTFIXED;
+			if (name[vp->name_len] == '=')
+				setvareq(savestr(name), VNOLOCAL);
+		}
+	}
+	lvp->vp = vp;
+	lvp->next = localvars;
+	localvars = lvp;
+	INTON;
+}
+
+
+/*
+ * Called after a function returns.
+ */
+
+void
+poplocalvars(void)
+{
+	struct localvar *lvp;
+	struct var *vp;
+
+	INTOFF;
+	while ((lvp = localvars) != NULL) {
+		localvars = lvp->next;
+		vp = lvp->vp;
+		if (vp == NULL) {	/* $- saved */
+			memcpy(optlist, lvp->text, sizeof optlist);
+			ckfree(lvp->text);
+			optschanged();
+		} else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
+			(void)unsetvar(vp->text);
+		} else {
+			if ((vp->flags & VTEXTFIXED) == 0)
+				ckfree(vp->text);
+			vp->flags = lvp->flags;
+			vp->text = lvp->text;
+		}
+		ckfree(lvp);
+	}
+	INTON;
+}
+
+
+int
+setvarcmd(int argc, char **argv)
+{
+	if (argc <= 2)
+		return unsetcmd(argc, argv);
+	else if (argc == 3)
+		setvar(argv[1], argv[2], 0);
+	else
+		error("too many arguments");
+	return 0;
+}
+
+
+/*
+ * The unset builtin command.
+ */
+
+int
+unsetcmd(int argc __unused, char **argv __unused)
+{
+	char **ap;
+	int i;
+	int flg_func = 0;
+	int flg_var = 0;
+	int ret = 0;
+
+	while ((i = nextopt("vf")) != '\0') {
+		if (i == 'f')
+			flg_func = 1;
+		else
+			flg_var = 1;
+	}
+	if (flg_func == 0 && flg_var == 0)
+		flg_var = 1;
+
+	INTOFF;
+	for (ap = argptr; *ap ; ap++) {
+		if (flg_func)
+			ret |= unsetfunc(*ap);
+		if (flg_var)
+			ret |= unsetvar(*ap);
+	}
+	INTON;
+	return ret;
+}
+
+
+/*
+ * Unset the specified variable.
+ * Called with interrupts off.
+ */
+
+int
+unsetvar(const char *s)
+{
+	struct var **vpp;
+	struct var *vp;
+
+	vp = find_var(s, &vpp, NULL);
+	if (vp == NULL)
+		return (0);
+	if (vp->flags & VREADONLY)
+		return (1);
+	if (vp->text[vp->name_len + 1] != '\0')
+		setvar(s, "", 0);
+	if ((vp->flags & VEXPORT) && localevar(vp->text)) {
+		change_env(s, 0);
+		setlocale(LC_ALL, "");
+		updatecharset();
+	}
+	vp->flags &= ~VEXPORT;
+	vp->flags |= VUNSET;
+	if ((vp->flags & VSTRFIXED) == 0) {
+		if ((vp->flags & VTEXTFIXED) == 0)
+			ckfree(vp->text);
+		*vpp = vp->next;
+		ckfree(vp);
+	}
+	return (0);
+}
+
+
+
+/*
+ * Returns true if the two strings specify the same variable.  The first
+ * variable name is terminated by '='; the second may be terminated by
+ * either '=' or '\0'.
+ */
+
+static int
+varequal(const char *p, const char *q)
+{
+	while (*p == *q++) {
+		if (*p++ == '=')
+			return 1;
+	}
+	if (*p == '=' && *(q - 1) == '\0')
+		return 1;
+	return 0;
+}
+
+/*
+ * Search for a variable.
+ * 'name' may be terminated by '=' or a NUL.
+ * vppp is set to the pointer to vp, or the list head if vp isn't found
+ * lenp is set to the number of characters in 'name'
+ */
+
+static struct var *
+find_var(const char *name, struct var ***vppp, int *lenp)
+{
+	unsigned int hashval;
+	int len;
+	struct var *vp, **vpp;
+	const char *p = name;
+
+	hashval = 0;
+	while (*p && *p != '=')
+		hashval = 2 * hashval + (unsigned char)*p++;
+	len = p - name;
+
+	if (lenp)
+		*lenp = len;
+	vpp = &vartab[hashval % VTABSIZE];
+	if (vppp)
+		*vppp = vpp;
+
+	for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) {
+		if (vp->name_len != len)
+			continue;
+		if (memcmp(vp->text, name, len) != 0)
+			continue;
+		if (vppp)
+			*vppp = vpp;
+		return vp;
+	}
+	return NULL;
+}
diff --git a/external/sh/var.h b/external/sh/var.h
new file mode 100644
index 00000000..ba8eda5a
--- /dev/null
+++ b/external/sh/var.h
@@ -0,0 +1,130 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)var.h	8.2 (Berkeley) 5/4/95
+ * $FreeBSD: head/bin/sh/var.h 279569 2015-03-03 21:21:43Z jilles $
+ */
+
+/*
+ * Shell variables.
+ */
+
+/* flags */
+#define VEXPORT		0x01	/* variable is exported */
+#define VREADONLY	0x02	/* variable cannot be modified */
+#define VSTRFIXED	0x04	/* variable struct is statically allocated */
+#define VTEXTFIXED	0x08	/* text is statically allocated */
+#define VSTACK		0x10	/* text is allocated on the stack */
+#define VUNSET		0x20	/* the variable is not set */
+#define VNOFUNC		0x40	/* don't call the callback function */
+#define VNOSET		0x80	/* do not set variable - just readonly test */
+#define VNOLOCAL	0x100	/* ignore forcelocal */
+
+
+struct var {
+	struct var *next;		/* next entry in hash list */
+	int flags;			/* flags are defined above */
+	int name_len;			/* length of name */
+	char *text;			/* name=value */
+	void (*func)(const char *);
+					/* function to be called when  */
+					/* the variable gets set/unset */
+};
+
+
+struct localvar {
+	struct localvar *next;		/* next local variable in list */
+	struct var *vp;			/* the variable that was made local */
+	int flags;			/* saved flags */
+	char *text;			/* saved text */
+};
+
+
+extern struct localvar *localvars;
+extern int forcelocal;
+
+extern struct var vifs;
+extern struct var vmail;
+extern struct var vmpath;
+extern struct var vpath;
+extern struct var vps1;
+extern struct var vps2;
+extern struct var vps4;
+extern struct var vdisvfork;
+#ifndef NO_HISTORY
+extern struct var vhistsize;
+extern struct var vterm;
+#endif
+
+extern int localeisutf8;
+/* The parser uses the locale that was in effect at startup. */
+extern int initial_localeisutf8;
+
+/*
+ * The following macros access the values of the above variables.
+ * They have to skip over the name.  They return the null string
+ * for unset variables.
+ */
+
+#define ifsval()	(vifs.text + 4)
+#define ifsset()	((vifs.flags & VUNSET) == 0)
+#define mailval()	(vmail.text + 5)
+#define mpathval()	(vmpath.text + 9)
+#define pathval()	(vpath.text + 5)
+#define ps1val()	(vps1.text + 4)
+#define ps2val()	(vps2.text + 4)
+#define ps4val()	(vps4.text + 4)
+#define optindval()	(voptind.text + 7)
+#ifndef NO_HISTORY
+#define histsizeval()	(vhistsize.text + 9)
+#define termval()	(vterm.text + 5)
+#endif
+
+#define mpathset()	((vmpath.flags & VUNSET) == 0)
+#define disvforkset()	((vdisvfork.flags & VUNSET) == 0)
+
+void initvar(void);
+void setvar(const char *, const char *, int);
+void setvareq(char *, int);
+struct strlist;
+void listsetvar(struct strlist *, int);
+char *lookupvar(const char *);
+char *bltinlookup(const char *, int);
+void bltinsetlocale(void);
+void bltinunsetlocale(void);
+void updatecharset(void);
+void initcharset(void);
+char **environment(void);
+int showvarscmd(int, char **);
+void mklocal(char *);
+void poplocalvars(void);
+int unsetvar(const char *);
+int setvarsafe(const char *, const char *, int);
diff --git a/external/update_sh.sh b/external/update_sh.sh
new file mode 100644
index 00000000..50307e87
--- /dev/null
+++ b/external/update_sh.sh
@@ -0,0 +1,32 @@
+#! /bin/sh
+set -e
+
+SH_DIR=$1
+if [ -z "${SH_DIR}" ]; then
+	echo "Usage: $0 /usr/src/bin/sh" >&2
+	exit 1
+fi
+DESTDIR=external/sh
+rm -rf "${DESTDIR}"
+mkdir -p "${DESTDIR}"
+DESTDIR_REAL="$(realpath "${DESTDIR}")"
+ORIG_PWD="${PWD}"
+cd "${SH_DIR}"
+export MK_TESTS=no
+make clean cleanobj
+make depend
+paths=$(make -V '${.PATH:N.*bltin*}'|xargs realpath)
+for src in *.h $(make -V SRCS); do
+	if [ -f "${src}" ]; then
+		echo "${PWD}/${src}"
+	else
+		for p in ${paths}; do
+			[ -f "${p}/${src}" ] && echo "${p}/${src}" && break
+		done
+	fi
+done | sort -u | tar -c -T - --exclude bltin -s ",.*/,,g" -f - | tar -C "${DESTDIR_REAL}" -xf -
+cp -R "${SH_DIR}/bltin" "${DESTDIR_REAL}/bltin"
+cd "${ORIG_PWD}"
+git add -A "${DESTDIR}"
+echo "sh_SOURCES= \\"
+find "${DESTDIR}" -name '*.c'|sed -e 's,$, \\,'