"In the command line" is a horribly wishy-washy windows-ism ("short" for command line interpreter/interface).
Linux/Mac has a _shell_ working within a _terminal_.
A "command line" is actually input passed to a program by the OS.
Discuss ;)
This is a pretty decent list of beginner-to-early-intermediate level tips, but it's worth noting that the majority of tips in the article are actually bash-isms, and won't work if you're on a different shell (though you might have equivalent features triggered by a different incantation)