8. Getting help about commands

Linux has two on-line documentation systems: man and info. There is a man page for every command on the system, while info is normally used to document applications from the Free Software Foundation, such as EMACS (a text editor) and gcc (a C compiler for programming).

man command

Display a manual page for the specified command. The "man" page provides a brief explanation about the command, possible options and switches and detailed information about using the command

apropos keyword

Displays a list of man pages that contain information about the supplied keyword