UNIX and Linux System Administration Handbook (5th Edition)
sed & awk
Code Complete: A Practical Handbook of Software Construction, Second Edition
Learning the bash Shell: Unix Shell Programming (In a Nutshell (O'Reilly))
Classic Shell Scripting
Designing Data-Intensive Applications: The Big Ideas Behind Reliable, Scalable, and Maintainable Systems
Mastering Regular Expressions
The Pragmatic Programmer: your journey to mastery, 20th Anniversary Edition (2nd Edition)
TCP/IP Illustrated, Vol. 1: The Protocols (Addison-Wesley Professional Computing Series)
Learning the vi and Vim Editors