man man

FreeBSD/Linux

How do manual pages work?

# FreeBSD example output
man man

MAN(1)                  FreeBSD General Commands Manual                 MAN(1)

NAME
     man – display online manual documentation pages

SYNOPSIS
     man [-adho] [-t | -w] [-M manpath] [-P pager] [-S mansect]
         [-m arch[:machine]] [-p [eprtv]] [mansect] page ...
     man -K regexp ...
     man -f keyword ...
     man -k keyword ...

DESCRIPTION
     The man utility finds and displays online manual documentation pages.  If
     mansect is provided, man restricts the search to the specific section of
     the manual.

     The sections of the manual are:
           1.   FreeBSD General Commands Manual
           2.   FreeBSD System Calls Manual
           3.   FreeBSD Library Functions Manual
           4.   FreeBSD Kernel Interfaces Manual
           5.   FreeBSD File Formats Manual
           6.   FreeBSD Games Manual
           7.   FreeBSD Miscellaneous Information Manual
           8.   FreeBSD System Manager's Manual
           9.   FreeBSD Kernel Developer's Manual
[...]