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.