Remove leading numbers from filename

Possibly my first post here, although I may have posted 6-ish years ago when I was ripping my whole CD library. At that time I was using mp3tag for Windows on a Mac using whatever procedure was in place then that made that work. I don't remember the details, but I had a good experience. Returning to it now, I find I've forgotten much of the little I learned.

So, first question: In mp3tag for Mac, it seems that the Filename - Filename option is missing from the Convert menu--yes? Why is that?

I'm trying to do something simple that I know is well within mp3tag's capabilities; I just can't remember (or just don't know) how. I'm working with pre-release music downloads; little effort is made to make the filenames user-friendly. One common thing is to include the disc and track number separated by an underscore, often after a numeric code. Stripping the numeric code is simple enough because it's the same for every track (every file). which leaves, eg, "01_09_Debussy Suite ..." I have already extracted the disc and track numbers; I'd just like to get rid of (eg) "01_09_" from the filename before rebuilding the filename (as, eg, DiscNo-Track name." So that's all really: Considering that it's different for every track, how do I, in a simple way, delete the first 6 characters from every fname? (I am not experienced using scripts, but I'm capable of it--just please provide practical details.)

Thanks,
Jim

See the FAQs on how to strip leading numbers:

I don't understand, though, why you first want to modify the filename

If your rebuild the filename, then the numbers will be gone anyway, I would think. Goiing straight for the refurbishing would save 1 step.

More information about MP3tag for Mac functions can be found in the documentation:

First, apologies for missing this in the FAQ. I did check, but I must have been impatient, not knowing where to look. I'm thinking that what you've quoted from "Regular Expressions" is just what I need.

Why rebuild the filename? Because currently it starts with (eg) 01_09_Debussy ... , and I want to get rid of the junk at the beginning before I do discnumber-track number filename, so that it doesn't read

01-09 01_09_Debussy ... .

Which should be easy now that I know how to use Regular Expressions.

Any idea why Convert filaneme - filename is missing in the Mac version?

Thanks,
Jim

What do your embedded tag fields look like?
Wouldn't it be much easier to use Convert>Tag-Filename and write a completely new filename?
Also, if you want to get from
01_09_
to
01-09
then try:
$regexp(%_filename%,_(\d+)_,-$1 )
In Convert >Tag-Tag for _FILENAME

Boy do I feel dumb. I had not bothered to look; I just assumed that the "title" tag was identical to the filename. Inexperience I guess. In fact, the title" tag does NOT have those first six characters, and I'm not sure why. (When I received the file, none of the tag fields were populated.) Is that something I did and forgot about, or is mp3tag just smart that way?

Anyway, that means I've been trying to solve a problem that doesn't exist. I just need to rebuild the filename, which is easy even for me.

Thanks,
Jim