Here’s a great site that should be in every linux user’s toolbox : Explain Shell.
It basically allows you type a command that you picked up from the web somewhere (or something burned in memory that you type out of sheer habit), and it shows what each argument to it actually does. For example, here’s a command I had to run recently that I had no clue about:
git pull -s recursive -X theirs upstream master
Paste that in the explainshell website and it coughs up a great explanation. Pretty useful when you don’t want to scroll through long man pages piecing together a particular command.