Linux bash or shell scripting

http://www.gnu.org/software/bash/manual/bashref.html

http://tldp.org/HOWTO/Bash-Prog-Intro-HOWTO.html

http://www.tldp.org/LDP/abs/html/

http://www.tldp.org/LDP/Bash-Beginners-Guide/html/

http://www.hypexr.org/bash_tutorial.php

http://mywiki.wooledge.org/BashGuide

http://conqueringthecommandline.com/book/_single-page