Hello. I was trying to play as a Bard in Diablo 1 and created a command.txt in my hellfire folder, and then added barbariantest;bardtest;cowquest;theoquest; into the command.txt, but whenever I start Hellfire, it does not show the new classes.

The exact directory I added the command.txt to was Local Disk>Program Files (x86)>GOG Galaxy>Games>Diablo>hellfire, and made sure to save the command.txt when added the text to it, but it doesn't work.

I've also tried it with spaces instead of semicolons and spaces with semicolons, but that doesn't work either.
Uninstalling and reinstalling the game also doesn't seem to do it.

If anyone has any suggestions, it would be most appreciated.

Thank you.

I can't see anything wrong with what you did so I can't directly address your issue... but, instead, I would suggest you try the "DevilutionX" community-made source port. That makes this stuff much easier to configure, and adds a bunch of (optional!) QoL on top.