regular expressions

What are they exactly? My VB book explains nothing about them and I know they're in PHP too but my php book says nothing about them either.

I just can't seem to find the information about them and what they are. Anyone got some links or something?

Regular Expressions are a syntax or language of its own kind of. It is a system of pattern matching. Maybe this will help:
http://www.fawcette.com/vsm/2003_01/...na/default.asp

and here's another helpfull link :
about regex

Thanks guys! Wow I didn't realize how useful regular expressions were!

I can't get my text box finding dialog to work correctly using the rich text box already exising function so I could just write a regular expression

and this one is useful too .
http://www.oreilly.com/catalog/regex...ter/index.html