Help with escape characters

[Malcolm]

I'm wondering if someone can point me to a nice tutorial on escape characters that would help me understand something like:
preg_match('#\s*(\[list(=("|"|\'|)([^\]]*)\\3)?\](.*)\[/list(=\\3\\4\\5)?\])\s*#si', $getList, $regs);

The kind of escape characters used in PHP/Shell scripting/Perl and the like.

Thanks :)

[Malcolm]

bahh, never mind. Farther searching has show me that these are 'Perl Compatible Regular Expressions', many tutorials found :)