I wrote this book really quickly as a way to bootstrap students for my other books. Many students don't know how to use the basics of the command line interface, and it was getting in the way of their learning. This book is designed to be something they can complete in about a day to a week and then get enough skill at the command line to graduate to other books.
This book isn't a book about master wizardry system administration. It's just a quick introduction to get newbies going.
For the price of most other course's PDFs only, you can get the full PDF for this class and 2 videos demonstrating the whole book for both Unix/OSX Terminal and Windows PowerShell. The course is self-paced so you can go through it any time you want, as many times as you want.