A website that will explain the workings of any Linux command in plain english.
http://explainshell.com/. This website allows you to type in a Linux command that you are unsure of and it will be explained to you in plain english. I just found this website linked in a Reddit posting and it is very cool indeed. Just type in a Linux command and what the command will actually do will be explained to you.
This would be very useful for any Linux user.