NGINX Cookbook
Derek Dejonghe
sed & awk
Dale Dougherty & Arnold Robbins
Cyber Security and Network Security
Sabyasachi Pramanik & Debabrata Samanta & M. Vinay & Abhijit Guha
Asterisk: The Definitive Guide
Jim Van Meggelen & Russell Bryant & Leif Madsen
Pluggable Authentication Modules
Kenneth Geisshirt