Good Unix Online Study Material

HI Friends,

I wanted to start this thread inorder to keep all the Unix starters to easily find useful material through this thread...I request you all to provide with the URL address of any gud material you know...

thanks and regards...

this is a very gud material for GDB learners

http://www.dirac.org/linux/gdb/

this is helpful for a novice in C to master in C programming.Carefully go through the EXERCISES in each chapter

http://www.cs.cf.ac.uk/Dave/C/