I would change the artist-name first and after changing rebuild the filename from the tags.
You could define actions group or - especially for newbies - it is easier to take the converter. The converter has a preview and it shows the result of your format-string-definitions.
Convert
Tag - Tag
Field: TITLE
Formatstring: $cutleft(%artist%,3)
This only works if there always 3 characters at the start.
Rebuilding the filename:
Tag - Filename
Formatstring: %artist% - %title%
That's helpful. Thanks. I never did get up to speed with regular expressions.
I use the cutLeft and mid/substr (whatever) functions to sort out Titles that have been copied from the filename - where the filename includes track number and album ...I have to modify the action each time, and count the characters.
To strip the track numbers, or replace the full stops/periods with hyphens (like replace "12." or "12. " with "12 - The Track Title"), I use RenamerNG (free program). Much easier (perhaps even if you're familiar with the mp3tag scripts/coding, because you can perform the actions on selected files, the Trim and Replace and Insert dialogs show you what the result will be, and you can Undo if it's messed-up.)
For the person asking how to use it. Use an action. See FAQ section on that and use the Replace with regular expression one.
From here choose the tag you want to affect, enter in that regular expression I posted and leave the replace with field blank if you ONLY want to do the same as the OP.
I doubt that anything could be easier and just as powerful as the functions in MP3tag.
You can do just the same things and many more with MP3tag, with the advantage that you do not have to leave MP3tag to start an external program which probably has no options to recycle any tag data.
I would think that it would be much better to get acquainted with the powers of MP3tag and leave that promoted program of yours where it is.
So i was facing a problem, the usual action suggested mostly wasn't behaving correctly because it was also removing the digits from some artists (ex.2 chainz, 20 fingers, 5 seconds of mars etc).
But the one suggested by @stevehero^\d+\s*[\.|-]\s* is removing only the tracknumbers.