If I ever get around to it, this might be useful
An in-depth exploration of the art of
shell scripting. A “must-have” guide for sys-admins, web-developers and
programmers working on Unix-like systems.
This tutorial assumes no
previous knowledge of scripting or programming, but progresses rapidly
toward an intermediate/advanced level of instruction . . . all the
while sneaking in little snippets of UNIX® wisdom and lore. It serves
as a textbook, a manual for self-study, and a reference and source of
knowledge on shell scripting techniques. The exercises and
heavily-commented examples invite active reader participation, under
the premise that the only way to really learn scripting is to write scripts.