Hale's the only person I know that really knows anything about regular expressions, other than the theory on how they are used. I needed to match a string that began with a space, then a '>' symbol and then another space, and remove it (or replace it with '' if you're thinking in terms of empty strings).

Simple enough, but I couldn't remember how to enforce the 'starts with' rule, meaning that it would only show a positive is the string began with the substring I was looking for. I know, it's basic, but I use regular expressions maybe once a month, so it's not like I am exposed to it daily...

In the end, I found it was:

/^ > /

... thanks to this really useful regular expression guide. It's written especially for Perl, but PHP uses Perl's regular expression through the preg_* range of functions, so it applied nicely.