I tried %_filename% MATCHES ^\l but that seems to return any filename that starts with a word character; it is not bringing me only filenames that start with lowercase letters. Grrr, what to do?
%_filename% MATCHES (?-i)^\l
You have to force the search function within mp3tag to search case sensitive. Not sure if its a bug or not but the (?-i) matches the remainder of the regexp as case sensitive.
If and I assume you want to change the 1st letter of the string to UPPER case then here is the action to match:
Action type: Replace with regular expression
Regular expression: ^([a-z])
Replace matches with: $upper($1)
Make sure case sensitive comparison is checked.
Thanks =) its actually because I was trying to delete spaces, hypens, periods and numbers that were before any of those characters but I ended up deleting that plus the first character of every single filename! I've just been semi-manually changing them all back (mp3tag crashed when I tried to undo changes). Sigh. I haven't had the time to learn codes so thanks very much for the reply.
But as the saying goes you always learn the hard way. So a good rule of thumb is to test on dummy/single files first.