Be familiar using linux. Learn important linux commands
http://community.linuxmint.com/tutorial/view/778 --> Most used commands
http://www.thegeekstuff.com/2010/11/50-linux-commands/ -> Extended list of important commands
https://www.youtube.com/watch?v=_TlK0-5EJ-Y -> Video showing how to use these commands
Be familiar with compilation, Makefile, editor, debugger
https://www.youtube.com/watch?v=gJFAeEYzY48 -> Video showing "hello world" coding and running
http://stackoverflow.com/questions/21548464/how-to-write-a-makefile-to-compile-a-simple-c-program -> Create makefile to compile hello.c
http://www.eclipse.org/downloads/packages/eclipse-ide-cc-developers/heliossr2 -> Try same with Eclipse editor
Learn linux OS internals and system calls