in MS-DOS, there was system call to change the "option switch" character. I don't remember what it was

API: int 0x21, ax=0x3700 = Get Switch Character, int 0x21, ax=0x3701 = Set Switch Character. Both available since MS-DOS 2.0, ignored since MS-DOS 4.01, changed to always return "/" since MS-DOS 5, DR-DOS 3.41 to 6.0.

Anchient DOS versions (MS DOS 2.x and some OEM versions) allowed setting the switch character in config.sys by setting SWITCHAR=x.

So yes, you could change the switch character (before MS-DOS 5), but most programs ignored it, and for those few which followed it, you had to rewrite batch files to use your switch character instead of the standard "/". Update to MS-DOS 5.0 would require another rewrite back to "/".

Alexander