Reddit reviews Classic Shell Scripting

If you want to learn BASH scripting, there are two that will get you on a very solid foundation:

1. Classical Shell Scripting
   
   
2. Advanced Bash Scripting Guide
   
   The first will teach you the basic tools available to you in the shell and how to approach problems in shell scripting by using all the resources available to you. It is one of the better programming books you'll find around.
   
   The second book will give you all the detail you need + lots and lots of code samples. I often use it as a reference before I take the plunge and do the self-torture that is man bash.

I consider Classic Shell Scripting by Robbins and Beebe to be the greatest book on the topic. It is so extensive yet readable that it is really worth getting a copy. I owe it to this book that I first really got into Unix as a whole. The authors speak from positions of vast experience and go out of their way to teach you the POSIX way, which is not only handy on exotic Unixes as opposed to Linux, but also on Debian and its derivatives now thanks to dash. Keeping scripts POSIX-compliant pay off a lot cause dash is (in my experience) 1.5 - 2 times faster in trivial looping applications.

Here is your bible: http://www.gnu.org/software/bash/manual/bashref.html

For some things to practice on:

http://adriann.github.io/programming_problems.html
/r/dailyprogrammer

And I find that once you get the 'fundamentals' down, taking similar complexity things from other languages and converting them to the one you are trying to learn is quite helpful.

If you were looking for a physical book, these two books cover quite a bit while being fairly cheap (20ish a piece):

http://www.amazon.com/Classic-Shell-Scripting-Arnold-Robbins/dp/0596005954/ref=cm_cr_dp_asin_lnk
http://www.amazon.com/Learning-bash-Shell-Programming-Nutshell/dp/0596009658

Also, for the one thing that made me go from 'how the fuck do I do that?!?' to 'I got this!' was running man test (man pages for test). I saw the syntax in tons of scripts, but didn't know how to google for it to figure out what it was doing.

EDIT: Forgot to add that if you type just plain help from the command line, you should get a dump of a lot of common commands. Helps if you forget syntax or forget the name of a function or are trying to discover new commands.

Just because textbooks and reference books can be dry doesn't mean they're not creative.

Here's another and another. O'Reilly published books have a couple clever or "funny" ones.

I found this book useful:
www.amazon.com/Classic-Shell-Scripting-Arnold-Robbins/dp/0596005954