I'm sure this has been covered to death but I'm going to ask anyway because what I'm trying to do is actually two different things, but at the same time. I can find answers for both individually, but not taken together, which is a problem.
My music collection has track numbers mostly in the form of "1/8" or "3/15" (for example) indicating both the actual track number and total tracks on the album. I'd like to rename the files with the inclusion of the track's number, but not the total number of tracks. I'd also like it to be 2 digits, including a leading 0 if needed.
Examples: Track with 3/15 would generate "03"; track with 12/20 would generate "12", etc.
In preparation for working with this, I've already created a custom tag, "TRACKNUM," which currently has the original TRACK tag contents in it. Anything I change will be done to that.