Classic Shell Scripting: Hidden Commands that Unlock the Power of Unix

Learning the bash Shell: Unix Shell Programming (In a Nutshell (O'Reilly))

sed & awk: UNIX Power Tools (Nutshell Handbooks)

bash Cookbook: Solutions and Examples for bash Users (Cookbooks (O'Reilly))

Bash Pocket Reference: Help for Power Users and Sys Admins

Mastering Regular Expressions: Understand Your Data and Be More Productive

Learning the vi and Vim Editors: Text Processing at Maximum Speed and Power

Wicked Cool Shell Scripts, 2nd Edition: 101 Scripts for Linux, OS X, and UNIX Systems

grep Pocket Reference: A Quick Pocket Reference for a Utility Every Unix User Needs (Pocket Reference (O'Reilly))

Shell Scripting: How to Automate Command Line Tasks Using Bash Scripting and Shell Programming

Linux Command Line and Shell Scripting Bible