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

Practical Vim: Edit Text at the Speed of Thought

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

Linux Command Line and Shell Scripting Bible

sed & awk: UNIX Power Tools (Nutshell Handbooks)

Bash Pocket Reference: Help for Power Users and Sys Admins

Mastering Regular Expressions: Understand Your Data and Be More Productive

Linux Pocket Guide: Essential Commands

Linux Bible

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