The most comprehensive documentation on FreeBSD is in
the form of man pages. Nearly every program
on the system comes with a short reference manual
explaining the basic operation and various arguments.
These manuals can be view with the
man command. Use of the
man command is simple:
mancommand
where command is the name of the command
you wish to learn about. For example, to learn more about
ls command type:
% man ls
The online manual is divided up into numbered
sections:
User commandsSystem calls and error numbersFunctions in the C librariesDevice driversFile formatsGames and other diversionsMiscellaneous informationSystem maintenance and operation commands
in some cases, the same topic may appear in more than
one section of the on-line manual. For example, there
is a chmod user command and a
chmod() system call. In this case,
you can tell the man command which
one you want by specifying the section:
% man 1 chmod
which will display the manual page for the user command
chmod. References to a particular
section of the on-line manual are traditionally placed
in parenthesis in written documentation, so
chmod(1) refers to the chmod
user command and chmod(2)
refers to the system call.
This is fine if you know the name of the command and
simply wish to know how to use it, but what if you cannot recall the
command name? You can use man to
search for keywords in the command descriptions by
using the -k switch:
% man -k mail
With this command you will be presented with a list of
commands that have the keyword `mail' in their
descriptions. This is actually functionally equivalent to
using the apropos command.
So, you are looking at all those fancy commands in
/usr/bin but do not even have the faintest idea
what most of them actually do? Simply do a
% cd /usr/bin; man -f *
or
% cd /usr/bin; whatis *
which does the same thing.
GNU Info files
FreeBSD includes many applications and utilities
produced by the Free Software Foundation (FSF). In
addition to man pages, these programs come with more
extensive hypertext documents called info
files which can be viewed with the info
command or, if you installed emacs, the info
mode of emacs.
To use the info(1) command, simply type:
% info For a brief
introduction, type h. For a quick
command reference, type ?.