Regular Expressions in Programming Languages and Operating System Utilities

1. A tutorial introduction to regular expressions in the Unix world
2. An interesting set of comments on the problems with regular expressions, particularly in Perl
3. Perl
   1. The Regex Coach: An interactive tool for experimenting with Perl-style regexes
   2. Regular expressions in Perl
   3. A short intro to regular expressions in Perl
   4. A regex example: primality testing
   5. Regular expression matching in Perl is NP-hard
4. How to write regular expressions in Python
5. Java
6. Grep
7. Majordomo

HTML and XML

1. W3C’s HTML page
2. W3C’s XML page
3. A DTD tutorial