a small document containing the definition of a command and its usage, to be consulted with the man command. The first thing one should (learn how to) read when learning of a command you aren't familiar with.

An entry in a UNIX reference manual. These entries can be accessed online using the man command. A letter in parentheses following a command or filename refers to the reference manual section where the command or file is documented. For example, the man command is documented in section C, Commands, of the Operating System User's Reference. They are also called ``man pages.''

Aformatted page for a specific command that describes the purpose of the command, its format and arguments, and a description of usage.

Send messages to someone not programmed into memory.