[moonboots]

A good intro is a talk given by Ryan Tomayko called the Shell Hater's Handbook[1]. His POSIX Shell and Utilities is also a great reference[2]. For a more comprehensive guide, I recommend the dash man pages[3]. Dash is shell, the good parts.

[1] http://shellhaters.heroku.com/ [2] http://shellhaters.heroku.com/posix [3] http://linux.die.net/man/1/dash

[b2hack]

This is very good. In any case I want a tutorial if possible. Something with exercises.