I got this book as a reference when working in the helpdesk at the university. It is very nice to have in hand when you're working in a unix/linux environment. All common commands is listed so you easily can browse through them, man-pages are nice but how often do you check out commands you havn't have a clue what they do? By browsing through this book I stumbled on a few more useful commands with examples on how to use thim to make nifty things. A few sections about the common shells and their different behavior are also included. Highly recommended to be placed near your keyboard, for reference.