Unix Fundamentals 101: From Shell Basics to Package Management
http://oreilly.com/go/unix101
Know the basics of Unix but looking for more? This set of hands-on, interactive tutorials will give you a foundational overview of the Unix operating system. Pull out your computer and follow along as industry experts walk you through how your computer starts up, how to use Shell and Proc, the basics of file systems and package management, and more.