The 'man' command

The command 'man' is Linux's built-in help system. If you don't know exactly how to use a command, or what it does, type 'man command' and you will see a summary of what the command does and how to use it.
Also, if the command you are looking up isn't explained when you try 'man command' it could be in another chapter of the man pages. Try using man 2 command, man 3 command etc. There are 8 chapters in all.

Usage:
'man command' or 'man x command'