I bought several books getting started. It was the Knoppix CD in the back of a magazine, forget the name now. Installing and running it.

Linux Basics for Hackers from @nostarch

If it hasn't been said, I really liked the Linux Phrasebook by Scott Granneman. I read it cover to cover, typing my way through the book to learn when I was starting out. amazon.com/Linux-Phrasebook-…

Not a book, but the OverTheWire: Bandit machine is a pretty nice basic and hands on introductory exercise.

Also, almost any book from the "Linux & BSD" selection from @nostarch is an excellent candidate. And there the "One Liners" (sed, awk, and perl) e-books from catonmat.net are nice references that have a good introductory explanation for the tools, as well.

I came to it via HP-UX and FreeBSD but if I was starting out now I’d read all the fantastic zines @b0rk has done