The description of man format expansion
The man file is a plain text document, which contains the help manual (called a “man page”), used by the Unix Man utility. The Unix Man is a program used to view documentation. The man file includes information about a Unix command or other Unix function. In addition, it can be viewed within a unix shell via using the man command.
Unix man pages quite rarely use the “man” extension. Instead, they apply the extensions from “1” (1 files) through “8” for user manuals in one of eight sections:
- General user commands
- System calls
- C library functions
- Devices and network interfaces
- File formats
- Linux-specific kernel routines.
Man page filenames contain the command (or topic name) followed by the section number. For instance, a section 1 man page for the command “example_cmd” would have the filename “example_cmd.1”. Man pages can also be compressed with gz algorithm and use the compound “gz.1” extension.
Man pages can be viewed by typing man [section] [page], where [section] is the man page section, and [page] is the user manual name. If no section is supplied, the man utility assumes section 1 by default.