A tool I can't help but pitch, since you seem interested in regular expressions. You might take a peek at PowerGREP. I had major hesitations about the price, but I wouldn't be without it now. I feel like suddenly all the information in pretty much any document type I have is entirely available to me both to extract information and to manipulate it. It has a free trial and you can access its full documentation. Incredibly powerful tool for a huge variety of tasks. If you only buy one thing from Goyvaerts, get RegexBuddy - which also includes a very nice GREP built in. But PowerGREP is...amazing. Feel free to PM me if you have some interest in that or his other tools - I shouldn't get further into it here.
(It's also - and this may sound silly - da bomb for accessing CHM and PDF help files! I'll stuff every reference I have for something into a folder and GREP the whole thing for a set of words within a specified number of words of any of another set of words - all in converted-to plain text (does this with a huge number of proprietary formats) with pointers back to the originals, and organized nicely with as many extra lines, or regex collection divisions, as you'd like - does this with html (ofc, considering the CHMs) too, and I'm starting to download parts of useful websites when I want things available to GREP from a site to additionally supplement a manual or whatever - I can GREP all these sources at once, and the output is very organized, readable, and not information overloading, even if I get a lot of results. Its sequencing features are also extremely versatile and powerful, as is its support for a wide variety of metadata - both read and write. And that doesn't get into what it's most used for, lol.)
But it's no file manager
