Try these at the command prompt:
Basically, the 'man' stands for manual pages, which are Unix/Linux's help system. There is another called 'info' that also includes a number of additional commands and instructions. Just type 'info' at the command line to use it. 'q' exits both.
More information is online at www.tldp.org
Oh, and 'apropos keyword
' can help you find what man page you are looking for.