These are some technical books that I have in English (EN) and Greek (GR) language.
Of course, I haven't read them all yet because I'm interested in specific chapters.
Operating Systems
UNIX in a Nutshell, 4th Edition [EN] - Arnold RobbinsLinux Server Security, 2nd Edition [EN] - Michael D. Bauer
C/C++
The C Programming Language, 3rd Edition [GR] - Brian Kernighan, Dennis RitchieTeach Yourself C, 3rd Edition [GR] - Herbert Schildt
Data Structures, Algorithms, and Applications in C++, 2nd Edition [GR] - Sahni Sartaj
Bash Shell
Learning the Bash Shell, 3rd Edition [EN] - Cameron Newham
PHP
Programming PHP, 2nd Edition [EN] - Rasmus Lerdorf, Kevin Tatroe, Peter MacIntyre
Python
Learning Python, 4th Edition [EN] - Mark LutzProgramming Python, 4th Edition [EN] - Mark Lutz