Learning the bash Shell, 3rd Edition
Cameron Newham
Linux System Programming
Robert Love
grep Pocket Reference
John Bambenek and Agnieszka Klus
Linux in a Nutshell
Ellen Siever & Stephen Figgins & Robert Love & and Arnold Robbins
Classic Shell Scripting
Arnold Robbins and Nelson H. F. Beebe
Linux Device Drivers, 3rd Edition
Jonathan Corbet & Alessandro Rubini & and Greg Kroah-Hartman
UNIX Power Tools, 3rd Edition
Jerry Peek & Shelley Powers & Tim O’Reilly & and Mike Loukides