How do you output a list of all man pages in a particular section?

A man page for fork, for example, is in the System Calls section that has number 2:

man 2 fork

How do you see what else is section 2 without resorting to Google?

Answers:

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Method 1

To list all installed man pages from a specific section you can use apropos:

apropos -s 2 .  # use an regex for apropos . means anything
apropos -s 2 -w '*'  # use unix globbing for apropos

Method 2

Manpages are usually placed in /usr/share/man, but check $MANPATH, and are organized into sections like so:

 Section 1:
 /usr/share/man/man1/

 Section 2:
 /usr/share/man/man2/

 ...

So to list all installed section 2 manpages, do:

ls /usr/share/man/man2/

Or the more complete one:

find $(echo $MANPATH | tr ':' ' ') -path '*/man2/*'

The latter one will have problems if you have directories in $MANPATH with space in their names.

On most distributions you can also check available man pages with a package tool, e.g. on Debian derived distributions you can use apt-file like so:

apt-file search /man2/

Method 3

This command lists the sorted names of all the entries in the given section:

man -aWS 1 * | xargs basename | sed 's/.[^.]*$//' | sort -u

If you want to see the pathnames, use:

man -aWS 1 * | sed 's/.[^.]*$//' | sort

This tells man to search a section for all commands using the wildcard pattern * (backslash-quoted so the shell doesn’t interpret it). -a finds all matches, -W prints the pathnames instead of displaying the pages, and -S 1 specifies section one. Change the 1 to whatever section you want to search.

The sed command strips the filename extensions; remove it if you want to see the complete filenames. sort sorts the results (-u removes duplicates).

For convenient reuse, this defines a Bash shell function:

function mansect { man -aWS ${1?man section not provided} * | xargs basename | sed 's/.[^.]*$//' | sort -u; }

For example, you can invoke it as mansect 3 to see the entries in section three.
[Tested on macOS.]

Method 4

On Mac OS X, the only thing I can get to work is man -k . | grep -F '(3)', which lists everything in section 3.

Method 5

I know this is a very old question, however the answers given here all didn’t work for me. Therefore I came up with the following one-liner that works on Ubuntu 18.04 and macOS Mojave, 10.14.6:

find $(man --path | tr ':' ' ') -type f -path '*man2*' 
  -exec basename {} ; | sed 's/..*//' | sort

Quick run down:

• form Thors answer: $(man --path | tr ':' ' ') to get the current paths of the man pages
• find <man paths> -type f -path '*man2*' -exec basename {} ; gets the file names of all regular files in the man paths
• sed gets rid of the file extension
• sort alphabetically.

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0