This is not a theoretical course; it is a very practical, hands-on course. To learn the stuff I expect you to learn, you must spend a lot of time on the computer trying things. Every time you read about a new command, or hear me describe one in lecture, try it. Invent new ways to use it, beyond what I or the textbook have described. Play with it. The best way to learn Unix is to use it until you don't even have to think about the most common commands -- your fingers know them by heart.