[TUHS] UNIX Backslash History

Paul Winalski paul.winalski at gmail.com
Tue Oct 29 06:43:16 AEST 2019

On 10/28/19, Dave Horsfall <dave at horsfall.org> wrote:
> On Mon, 28 Oct 2019, Steve Nickolas wrote:
>> 86-DOS actually did use ":" as a prompt character.  This was changed for
>> IBM's release, for some clone releases, and for MS-DOS 2.0.
> The best I've ever seen was RT-11's "." - talk about minimalist...
> Actually this thread probably belongs on COFF by now.

RT-11 was following standard DEC practice by using "." as its command
prompt.  The "monitor dot" was the command prompt in both TOPS-10 and

Most DEC operating systems, including RT-11, TOPS-10/20, and VMS, used
"/" as a prefix on command options; "-" performs this function on UNIX
since "/" is the directory delimiter.  Back in the days of stand-alone
programs, physical switches on the console were used to set program
options.  This of course won't work when you have multiprogramming.  I
was told that DEC chose "/" because it looks like a toggle switch.
Command options in fact were initially called "switches".

-Paul W.

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