Penetration Testing: A Hands-On Introduction to Hacking
Gorgia Weidman
Quick Start Guide
John Schember
Serious Cryptography
Jean-Philipee Aumasson
Cybersecurity Ops with bash
Paul Troncone & Carl Albing Ph.D.
Linux in a Nutshell
Ellen Siever & Stephen Figgins & Robert Love & Arnold Robbins
The Linux Command Line, 2nd Edition
William Shotts
Classic Shell Scripting
Arnold Robbins & Nelson H. F. Beebe
Effective Awk Programming
Arnold Robbins
Unix Power Tools
Shelley Powers
Linux Basics for Hackers
OccupyTheWeb
Linux System Programming
Robert Love
Linux Device Drivers
Jonathan Corbet & Alessandro Rubini & Greg Kroah-Hartman
Linux Pocket Guide
Daniel J. Barrett
grep Pocket Reference
John Bambenek & Agnieszka Klus
Bash Cookbook
Carl Albing & JP Vossen