Unix was originally written by developers at ATT Bell labs in the late 60's for their own personal projects. It was created to let them do tasks quickly and easily, and its growth over time has been fairly organic, as other developers, admins, and geeks have added their contributions.

One of the results of this is that the documentation on a unix/linux system tends to be fairly terse. It is written to provide information quickly, with as little overhead as possible. This can make it hard for someone new to unix to interpret the documentation, as it is frequently written for other admins or developers, not for people just starting out. So to help those starting out I'd like to explain a little bit about the man(ual) pages.

Man pages are the traditional documentation included with an unix system that explain the commands, system files, and other parts of the system that you may need to use. Man pages are divided into sections, with each section dealing with a different aspect of the system. There are 8 sections that are fairly consistent across varients of unix/linux:
1 Executable programs or shell commands
2 System calls (functions provided by the kernel)
3 Library calls (functions within program libraries)
4 Special files (usually found in /dev)
5 File formats and conventions eg /etc/passwd
6 Games
7 Miscellaneous (including macro packages and conven‐
tions), e.g. man(7), groff(7)
8 System administration commands (usually only for root)
Note that its common to see other sections on modern linux boxes (I've seen sections 0, 9, N, and P on various distros), and these other sections will have information on other things. However these 8 sections will be on every system, and will cover the same information on each system. If you find other sections on your system the documentation on your system should explain what additional information is contained in them.

Man pages can be viewed by using the man command, whose basic syntax is
man command
replacing the word command with the command you want information on. Each man page will be divided into sections, which should always appear in the following order: Name, Synopsis, Description, Options, Files, See Also, Bugs, and Author. Not every one of these sections need appear in a single man page, but the sections that are there for a particular man page will appear in the above order. To keep this simple I am ignoring differences in the man pages related to system calls and library functions, as these sections will be of more interest to programmers, and if you need to use those sections then you shouldn't need this article to tell you how to use man pages.

The Name section will list the name of the program or file, and often a 1-2 line explanation. For commands the Synopsis section will then show the various ways that the command can be used, giving the command's syntax. The text in the Synopsis follows some conventions, to help you understand what to type, which I used in showing the man command above. Text in bold should be entered on the command line exactly as its seen in the man page. Text in italics should be replaced with an actual value. Any text inclosed by square brackets [] is optional, meaning you don't have to include it if you don't want to. Items that can be repeated are followed by ... , and things that can't be used together at the same time will be separated by a |.

The Description section will then provide a more detailed explanation of what a command is supposed to do, while the Option section will list each of the options available with the command, as well as an explanation of what that option does and how to use any parameters that are part of the option.

The Files and See Also sections tell you which files the command uses, and what man pages are available for related commands or files respectively. The Bugs section should mention any known bugs that the command currently has, and the Authors section tells you who wrote the command.

When you look at the See Also section you'll notice that there is a number in parentheses after each item. This tells you which section that man page is in. Sometimes there will be man pages in different sections that have the same name. A good example of this would be passwd, which is both a command and a file. As a result there are man pages in both sections 1 and 5 for passwd. When the man command is used it will search the different sections in order, so simply typing
man passwd
will always give you the man page for the passwd command. You can however specify which section you want to use by specifying it before you specify the page you want. So to look at the man page for the passwd file you would use the command
man 5 passwd