A Pretty Good Shell Scripting Primer

I stumbled upon a pretty good document in Apple's Developer Connection - Shell Scripting Primer. I particularly like the "Designing Scripts for Cross-Platform Deployment" and "Performance Tuning" chapters.

Here is the table of contents:

1. Shell Script Basics
2. Result Codes, Subroutines, Scoping, Sourcing
3. Paint by Numbers
4. Regular Expressiopns Unfettered
5. How awk-ward
6. Designing Scripts for Cross-Platform Deployment
7. Advanced Techniques
8. Performance Tuning
9. Appendix A: Other Tools and Information
10. Appendix B: An Extreme Example: The Monte Carlo (Bourne) Method for Pi