On Tue, Nov 28, 2017 at 2:36 PM, Paul Winalski <paul.winalski@gmail.com> wrote:
MS/DOS patterned its command line
​ ​
syntax after RT-11 and inherited the slash as a command option
introduction from there.
Minor correction...   To do a CDC style patient zero history ;-) RT11 took it from DOS/8, CP/M took it from RT11, then finally DOS-86 which became PC-DOS ney MS/DOS took it from CP/M.