The funny thing is that if I had been asked this question a few years ago I would have answered of course I know regexps without much thought. Does that mean that I know less about regular expression now than I did then? No, I know more. I now know enough to know that I don't know them.
The Zen of regular expressions:
The first step towards knowing regular expressions is to realize you do not know them.
Since I'm just starting to reach this first step, I cannot tell what the next step will be... or how many steps there are. :)