It's true that DOS was originally a CP/M clone, but CP/M didn't have a defined standard option switch character, and in fact many command option switches weren'

It's true that DOS was originally a CP/M clone, but CP/M didn't have a defined standard option switch character, and in fact many command option switches weren't preceded by a switch indicator or differed as to what option switch character was used. If anything + and - were the most common prefixes for an option switch. http://www.cpm.z80.de/manuals/cpm3-cmd.pdf http://www.cpm.z80.de/manuals/cpm3-cmd.pdf The article is quite right that the convention of using / for command line switches came from IBM.