Earlier quoted context omitted.
> Why didn't they push this instead of the very limited MS-DOS? Hardware requirements. For a (quite long) while the plan was to keep DOS for microcomputers and Xenix for the serious stuff. DOS gained some extensions that made it very Xenix/UNIX-like (like subdirectories, pipes, "-" as command line switch char, device files in "\dev" instead of a global namespace, etc.).
While MSDOS had subdirectories, pipes were not supported at the kernel level. It was simply a convenience of COMMAND.COM that simulated pipes by running each command sequentially. The command switch character was the slash (/) until the end, with the exception of a few non-standard third-party softwares insisting on the dash. Device names were always global namespace and \dev never existed in any form. Did you copy-p…
MS-DOS 1.x did not have subdirectories.
That came in with MS-DOS 2.x which is when the very rudimentary level of Xenix compatibility came in: device names such as `LPT1:` or `COM2:` could be prefixed as `/dev/lpt1` or `/dev/com2`. Pipes simulated in COMMAND.COM.
I don't recall DOS ever accepting command switches prefixed with `-` instead of `\` as standard, though.