[TUHS] Dash options

Paul Winalski paul.winalski at gmail.com
Wed Nov 29 05:36:21 AEST 2017

On 11/28/17, Andrew Warkentin <andreww591 at gmail.com> wrote:
> Multics had dash options, so that's presumably where Unix got them
> from. I believe slash options were mostly a DEC thing that DOS and its
> successors borrowed (I think they originated in TOPS-10).

That's how I remember it.  I think slash was chosen because it looks
somewhat like a toggle switch.  MS/DOS patterned its command line
syntax after RT-11 and inherited the slash as a command option
introduction from there.  Unfortunately this meant that they couldn't
use slash as a directory separator when they got a hierarchical file
system, and so they chose backslash instead.  Nowadays the Windows
shell, and I think also the underlying image activation system
service, use an ugly algorithmic hack to support both directions of
slashes in file pathnames.

-Paul W.

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