*nix commands (and functions?) have a number with them, like
What does the number mean?
The character explicitly specifies the section that the manual page is part of. On most Unices, the section definitions are as follows:
SysV has a similar, but not identical structure:
On some systems, the following sections also exist:
The number is the manpage it refers to. Each manpage has its own purpose, like beeing the manpage for the POSIX definition or specific linux definition (for programmers) or the manpage for the tools usage itself, if you can invoke it from the commandline.
the purpose of the specific manpage is covered in the first section
will show you the specific page
will show you page after page after you quit with
In addition to the answers already provided. Keep in mind that some Unix don't have the 8 number in their man's categories, but have the 1M instead.