Where can I find all the documentation for mac's builtin shell commands?

Question

The OS X Man Pages lists out all builtin functions. But where can I find the documentation of a particular one?

For instance, the command fc, on ubuntu I can get its manual by:

> help fc
fc: fc [-e ename] [-lnr] [first] [last] or fc -s [pat=rep] [command]
Display or execute commands from the history list.

fc is used to list or edit and re-execute commands from the history list.
FIRST and LAST can be numbers specifying the range, or FIRST can be a
string, which means the most recent command beginning with that
string.
....

Another example is the if expression, on ubuntu:

> help if
if: if COMMANDS; then COMMANDS; [ elif COMMANDS; then COMMANDS; ]... [ else COMMANDS; ] fi
Execute commands based on conditional.
...

What am I missing here?

Slightly unrelated to the question but I find the tldr pages command to be very useful for reading up on other commands in general :) — Hoi_A, Feb 21 '17 at 13:14
@Hoi_A Indeed tldr is a very handy tool with succinct examples. It just happens that some builtin functions were missing from tldr. E.g. hash, fc ,etc. Perhaps will open an issue there — user2829759, Feb 22 '17 at 17:03
I did not know that, I always assumed they had covered all main commands. You could probably just add it to tldr directly instead of an issue since they welcome contributions :) — Hoi_A, Feb 22 '17 at 17:04
zsh has it own help function called run-help. You will find information on setting up run-help in man zshcontrib. — fd0, Feb 22 '17 at 18:29
if you have installed tldr, try tldr fc ; gives quick examples if that is what you like. — Robert Ranjan, Feb 08 '22 at 22:21
See also https://apple.stackexchange.com/questions/239484/does-apple-provide-a-web-site-with-content-of-man-pages-for-the-command-line-c — cachius, Jun 13 '23 at 04:39

score 12 · Answer 1 · answered Apr 21 '20 at 21:25

12

On macOS Catalina (10.15) and above, use:

man zshbuiltins

That's because zsh is now the default shell on Mac (not bash). As you and @Ricardo noted in the comments above, you can't use help in zsh.

answered Apr 21 '20 at 21:25

superbatfish

221
2
3

1

Other than some scripting on that man page, is there a way to get run-help work on MacOS? – RexYuan Jan 04 '21 at 15:42

score 11 · Accepted Answer · answered Feb 21 '17 at 06:15

You do the exact same thing.

So...

$ help if
if: if COMMANDS; then COMMANDS; [ elif COMMANDS; then COMMANDS; ]... [ else COMMANDS; ] fi
    The `if COMMANDS' list is executed.  If its exit status is zero, then the
    `then COMMANDS' list is executed.  Otherwise, each `elif COMMANDS' list is
    executed in turn, and if its exit status is zero, the corresponding
    `then COMMANDS' list is executed and the if command completes.  Otherwise,
    the `else COMMANDS' list is executed, if present.  The exit status of the
    entire construct is the exit status of the last command executed, or zero
    if no condition tested true.

Or...

$ help fc
fc: fc [-e ename] [-nlr] [first] [last] or fc -s [pat=rep] [cmd]
    fc is used to list or edit and re-execute commands from the history list.
    FIRST and LAST can be numbers specifying the range, or FIRST can be a
    string, which means the most recent command beginning with that
    string.

       -e ENAME selects which editor to use.  Default is FCEDIT, then EDITOR,
          then vi.

       -l means list lines instead of editing.
       -n means no line numbers listed.
       -r means reverse the order of the lines (making it newest listed first).

    With the `fc -s [pat=rep ...] [command]' format, the command is
    re-executed after the substitution OLD=NEW is performed.

    A useful alias to use with this is r='fc -s', so that typing `r cc'
    runs the last command beginning with `cc' and typing `r' re-executes
    the last command.

you an also use the "man" command: "man fc" will give you the manual pages for the "fc" command — Steve Chambers, Feb 21 '17 at 16:03
man fc will give you the page for all builtin shell commands (for csh and sh) without any usage details of any of them. Basically, exactly what the OP linked to in the question. — Patrick Wynne, Feb 21 '17 at 16:16

score 1 · Answer 3 · answered Feb 03 '22 at 18:35

run-help would work, but is aliased to man. based on man zshcontrib:

To use the run-help function, you need to add lines something like the following to your .zshrc or equivalent startup file:

          unalias run-help
          autoload run-help

Pressing the escape then H may also work, if you still have default keybinds in place.

ranemirusG · Answer 4 · 2022-10-15T13:17:29.273

1

zshbuiltins as noted above is the correct answer.

In man builtin we can read:

Consult a shell's manual page for details on the operation of its builtin commands.

zshbuiltins is part of man zsh.

This YouTube video is pedagogical and may be usefull for begginers (like me).

edited Oct 15 '22 at 13:17

answered Oct 15 '22 at 12:59

ranemirusG

11
4

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Whilst this may theoretically answer the question, it would be preferable to include the essential parts of the answer here, and provide the link for reference. – agarza Oct 15 '22 at 13:03
Thx but how is your answer actually any different than the answer by @superbatfish to the question? If you just wanted to share the video, you should have shared it as a comment when you have enough reputation points. – Alper Oct 16 '22 at 19:42
This does not provide an answer to the question. Once you have sufficient reputation you will be able to comment on any post; instead, provide answers that don't require clarification from the asker. - From Review – Alper Oct 16 '22 at 19:44

Where can I find all the documentation for mac's builtin shell commands?

4 Answers4