1 files changed, 20 insertions, 0 deletions
diff --git a/Documentation/CodingGuidelines b/Documentation/CodingGuidelines
index 483008699f..57da6aadeb 100644
--- a/Documentation/CodingGuidelines
+++ b/Documentation/CodingGuidelines
@@ -35,10 +35,22 @@ For shell scripts specifically (not exhaustive):
 
  - Case arms are indented at the same depth as case and esac lines.
 
+ - Redirection operators should be written with space before, but no
+   space after them.  In other words, write 'echo test >"$file"'
+   instead of 'echo test> $file' or 'echo test > $file'.  Note that
+   even though it is not required by POSIX to double-quote the
+   redirection target in a variable (as shown above), our code does so
+   because some versions of bash issue a warning without the quotes.
+
  - We prefer $( ... ) for command substitution; unlike ``, it
    properly nests.  It should have been the way Bourne spelled
    it from day one, but unfortunately isn't.
 
+ - If you want to find out if a command is available on the user's
+   $PATH, you should use 'type <command>', instead of 'which <command>'.
+   The output of 'which' is not machine parseable and its exit code
+   is not reliable across platforms.
+
  - We use POSIX compliant parameter substitutions and avoid bashisms;
    namely:
 
@@ -64,11 +76,19 @@ For shell scripts specifically (not exhaustive):
 
  - We do not use Process Substitution <(list) or >(list).
 
+ - Do not write control structures on a single line with semicolon.
+   "then" should be on the next line for if statements, and "do"
+   should be on the next line for "while" and "for".
+
  - We prefer "test" over "[ ... ]".
 
  - We do not write the noiseword "function" in front of shell
    functions.
 
+ - We prefer a space between the function name and the parentheses. The
+   opening "{" should also be on the same line.
+   E.g.: my_function () {
+
  - As to use of grep, stick to a subset of BRE (namely, no \{m,n\},
    [::], [==], nor [..]) for portability.