Classic Shell Scripting
Arnold Robbins & Nelson H. F. Beebe
Quick Start Guide
John Schember
Metasploit: The Penetration Tester's Guide
David Kennedy, Jim O'Gorman, Devon Kearns, Mati Aharoni
Volo's Guide to Monsters
Dungeons & Dragons
Bash Cookbook
Carl Albing & JP Vossen
Cybersecurity Ops with bash
Paul Troncone & Carl Albing Ph.D.
Effective Awk Programming
Arnold Robbins
grep Pocket Reference
John Bambenek & Agnieszka Klus
Linux Basics for Hackers
OccupyTheWeb
The Linux Command Line, 2nd Edition
William Shotts
Linux Device Drivers
Jonathan Corbet & Alessandro Rubini & Greg Kroah-Hartman
Linux in a Nutshell
Ellen Siever & Stephen Figgins & Robert Love & Arnold Robbins
Linux Pocket Guide
Daniel J. Barrett
Linux System Programming
Robert Love
Unix Power Tools
Shelley Powers