GitHub For Dummies
Sarah Guthals & Phil Haack
CyBOK
Awais Rashid & Howard Chivers & George Danezis & Emil Lupu & Andrew Martin
Linux iptables Pocket Reference
Gregor N. Purdy
Mastering Linux Network Administration
Jay LaCroix
The Complete Metasploit Guide
Sagar Rahalkar
The the Complete Metasploit Guide
Sagar Rahalkar & Nipun Jaswal