Almost all substantial UNIX and Unix-like operating systems have extensive documentation available as an electronic manual, split into multiple sections.
To read a page from the manual, one can use the command
$ man [<section>] <page_name>
at a shell prompt, e.g. "man ftp" (the section number can usually be omitted).
Pages are traditionally referred to using the notation "page_name(section)", e.g. ftp(1).
The section number is used to allow a specific manual page to be chosen when there are multiple manual pages with the same name. This can occur when the names of system calls, user commands, or macro packages[?] conflict. Two examples are man(1) and man(7), or exit(1) and exit(3).
The manual is generally split into eight numbered sections, organised as follows:
| Section |
Description |
| 1 |
General commands |
| 2 |
Low-level system calls |
| 3 |
C library functions |
| 4 |
Special files (usually devices, those found in /dev) |
| 5 |
File formats and conventions |
| 6 |
Games |
| 7 |
Miscellanea |
| 8 |
System administration and associated commands |
On some systems some of three other sections are available:
The manual pages are stored as nroff source files.
Most versions of man cache the formatted versions of the last several pages viewed.
For an example of a man page see chmod.
This article was originally based on material from FOLDOC, used with permission. Update as needed.