doctor: add new subcommand

This command will diagnose user's environment and let
the user know some recommended solutions if they
potentially have any problems related to npm.

Credit: @watilde
Reviewed-By: @othiym23
Reviewed-By: @iarna
PR-URL: https://github.com/npm/npm/pull/14582
Fixes: #6756

1 files changed, 44 insertions, 0 deletions

diff --git a/doc/cli/npm-doctor.md b/doc/cli/npm-doctor.md
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+npm-doctor(1) -- Check your environments
+========================================================
+
+## SYNOPSIS
+
+    npm doctor
+
+## DESCRIPTION
+
+npm command is just a single command, but depends on several things outside
+the code base. Broadly speaking, it is the following three types:
+
++ Technology stack: Node.js, git
++ Registry: `registry.npmjs.com`
++ Files: `node_modules` in local/global, cached files in `npm config get cache`
+
+Without all of these working properly, the npm command will not work properly.
+Many issue reports that arrive under us are often attributable to things that
+are outside the code base as described above, and it is necessary to confirm
+that this is correctly set with one command would help you solve your issue.
+Also, in addition to this, there are also very many issue reports due to using
+old versions of npm. Since npm is constantly improving, in every aspect the
+`latest` npm is better than the old version(it should be, and we are trying).
+
+From the above reasons, `npm doctor` will investigate the following items in
+your environment and if there are any other recommended settings, it will
+display the recommended example.
+
+|What to check|What we recommend|
+|---|---|
+|`npm ping`|It must be able to communicate with the registry|
+|`npm -v`|It is preferable that the latest version of LTS is used|
+|`node -v`|It is preferable that the latest version of LTS is used|
+|`npm config get registry`|In order not to consider exceptions, it is better to set default values `registry.npmjs.org`|
+|`which git`|Git has to be installed|
+|`Perms check on cached files`|All cached module files must be readable.|
+|`Perms check on global node_modules`|All global module files must be executable.|
+|`Perms check on local node_modules`|All local module files must be executable.|
+|`Checksum cached files`|All cached files must not be broken|
+
+## SEE ALSO
+
+* npm-bugs(1)
+* npm-help(1)