Shell script programming is an essential skill of Unix/Linux/Cygwin users. With the support of dozens of utilities, the shell script could be multi-purpose Swiss knife to improve our productivity and ease our work load. It's really useful. Hopefully you guys can get help from the below tutorials that I collected,
Linux Shell Scripting Tutorial v1.05r3A Beginner's handbook
http://www.freeos.com/guides/lsst/
Unix Shell Scripting Tutorial
Bash Guide for Beginners
http://tldp.org/LDP/Bash-Beginners-Guide/Bash-Beginners-Guide.pdf
Advanced Bash-Scripting Guide
http://tldp.org/LDP/abs/abs-guide.pdf