Great! Glad it's (sort of) working for you.
If it's any help, the text editor I mostly use on the Mac, Smultron, says that it uses ICU Regular Expressions
, which are apparently quite common and used in many platforms/apps.
ICU have a kind of user guide
(well, more like tersely commented documentation on what stuff does, but there's a couple of examples and tips on how to get the result you want) on their website.
And you might have to tweak the stuff in the  range brackets if you're reading a language with accents, or something with fancy punctuation in the titles. I tried to put in all the stuff I could reasonably think of that people would put into English-language chapter names.