Ah, actually i don't think that is what im trying to do. Right now, the album field already says all of this " [BT 03] - 1995 - Spikey Trance" and the catalog # tag is blank. I want catalog # to say "BT 03"
My brother suggested maybe first, simply copy album field to catalog #, then use something like
$regexp(%catalog #%, "^\.*[(.*?)\].*$", $1)
on the catalog # field to keep only whats inside the brackets
and
$regexp(%album%, "[(.*?)\] ?", "")
on the album field to remove the brackets and everything inside them (as i don't want the catalog number in album field once its copied over to the catalog # field
perhaps that code needs correcting. I don't know if there's a better way