I’m sure you’ll be able to find plenty of information about shell scripting on the net. When I wrote this text (started 1999, with some updates until 2005) there wasn’t a good german introduction.
If you can read german: here’s the download.
Initially, I wrote this text for a school project. It quickly became too long to be a handout, so I published it on my page.
The Wikibooks project took the text from SelfLinux.
Both of those sites enhanced my text on their own, I see them as forks of my project.