If you do a search for Linux guides and you will find lots such as this one:
http://tldp.org/LDP/abs/html/

I print them as pdfs for future use. You can do that in Linux going to File,
Print and choose Print to File from the choice of printers. Click on pdf and
give it a name.

Also useful are the man pages. In a terminal windows type man <command> and
it will tell you the syntax and switches. You can also type man <command> in
a browser window.