Raspbian includes thousands of terminal commands, each one with its own set of flags and options. Since it is impossible to remember all of the commands and their options, Linux distributions (including Raspbian) include a program called man (short for manual page). The purpose of this program is to display information about a command. For example, to find out more information about the ls command, simply type man ls in the terminal:
The man ls command will display all information about the ls command – how it is invoked, its purpose, options, flags, description, etc:
Note that the less program is used to display information. To display the next page of the output, press Space. To move up and down a page, press the Page Up and Page Down keys. To display all keys available in less, press h. To quit less, press q.
If you don’t know the name of the command for something you would like to do, you can use the man command to search for the desired command. For example, if you would like to cancel print jobs but don’t know the exact command, you can type man -k cancel command to get the name of the command:
The man -k cancel command displayed all commands with the word cancel in their name or description. The command we are looking for is lprm.