Wow! I can't believe I didn't' stumble on this post before. These presets are incredibly useful!
I have tried to tweak a couple of them to suit my needs. For the "Swap Artists" preset, I changed it so that it would just swap words between a dash (as long as there is only one dash). So for example, if I have a book named "Lewis Carroll - Alice in Wonderland.pdf" it would change it to "Alice in Wonderland - Lewis Carroll.pdf". So I tried the following:
Regexp (.+) - (.+) to \2 - \1
It works, but the problem is that the extension is also swapped, so that it results in:
"Alice in Wonderland.pdf - Lewis Carroll"
Is there anyway for me to change the code so that I can avoid swapping the extension?
Just in case anyone else is interested, solution can be found here:
(2017: Also note that with Opus 12 you can just turn on ignore extension to avoid having to worry about the file extension when changing the rest of the name.)