Unix Shells By Example

Classic Shell Scripting

Unix Shell Programming (3rd Edition)

Murach's Oracle SQL and PL/SQL for Developers, 2nd Edition

UNIX and Linux System Administration Handbook, 4th Edition

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

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

Linux Pocket Guide: Essential Commands

Linux Bible

A Practical Guide to the UNIX System (3rd Edition)

sed & awk