It’s very usable; best to go through the intro and basics, then look up what you need to do for a specific task. I only know of three current books about using Mac OS Terminal; this one, DanielPlatt’s Tweak Your Mac Terminal, and the currently OOP Mastering Mac OS Terminal. I prefer this one, with Platt’s a distant second.
This one could use more examples, but it’s easy to follow.
Looks like Take Control Terminal is a good start for a Terminal noob like me. I am also interested in Apple Script but it does not looks like there’s a Take Control on this.