System Programming Books
Keep focus on : ipc mechanisms, memory, processes,
signals, debugging, threading, networking/sockets, development tools, make etc
You can skip things like X window etc
Buy some of the following books and read these. They are
available online too.
Try to read them in parallel and different chapters will
also do.
(1) The Linux Programming Interface : A Linux and UNIX®
System Programming Handbook
by Michael
Kerrisk
(2) Advanced Linux Programming :
advancedlinuxprogramming.com
(3) Linux System Programming : Robert Love
(4) Begininng Linux Programming : Wrox