I've had very little experience with Linux but now that I'm using Raspberry Pis (a cheap single board computer that runs Linux) I need to know how to use Linux. Online how-tos are good, but Linux for Makers, by Aaron Newcomb, is better. In fact, this book is pure gold. It assumes zero prior knowledge of Linux. Everything is clearly explained. I learned how to install Raspbian Linux on an SD Card (Raspberry Pis use SD cards as their hard drive), log the output of a script, schedule jobs with cron, use lots of different commands, write scripts, use PI with IFTTT, and lots more.