The most comprehensive documentation on FreeBSD is in the form of manual pages. Nearly
every program on the system comes with a short reference manual explaining the basic
operation and various arguments. These manuals can be viewed with the man command. Use of the man command is
simple:
% man command
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 commands.
-
System calls and error numbers.
-
Functions in the C libraries.
-
Device drivers.
-
File formats.
-
Games and other diversions.
-
Miscellaneous information.
-
System maintenance and operation commands.
-
Kernel developers.
In some cases, the same topic may appear in more than one section of the online
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
This will display the manual page for the user command chmod.
References to a particular section of the online 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 have the faintest idea what most of them actually do? Simply do:
% cd /usr/bin
% man -f *
or
% cd /usr/bin
% whatis *
which does the same thing.
FreeBSD includes many applications and utilities produced by the Free Software
Foundation (FSF). In addition to manual 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 ?.