I have a growing collection of songpro files named like *.pro within a particular folder structure. Briefly, songpro files contain text sequences that indicate general, lyric, and chord information about a song, useful for specialized programs that organize and display songs in a playable format for musicians.

My quest is to find those files (not lines) that contain a tag like

{artist:some artist}

but do not contain the tag like

{tag:some artist}

(I am not concerned with any text between the colon and the closing brace, which necessarily may not match between tag and artist; I only want to know that one but not both of these tags exist.)

I have found sites (like this one) that show how to find exclusively one of two words on a LINE, but have not found a way to show FILEs that contain one of two words. Note that {tag:some tag}{artist:some artist}{tag:some artist} (on one line) is valid... and that {artist:...} and {tag:...} may appear multiple times within a file, and in any order.

{tag:Beatles}{artist:The Beatles}{artist:Paul McCartney}
{tag:Love songs}