[TUHS] Pipes (was Re: After 50 years, what has the Impact of Unix been?)

[arnold at skeeve.com]

Chet Ramey via TUHS <tuhs at tuhs.org> wrote:

> On 12/5/24 10:19 AM, Dan Cross wrote:
>
> > Unix pipelines, on the other hand, tend to be used in a manner that is
> > strictly linear, without the fan-out and fan-in capabilities described
> > by Morrison. Of course, nothing prevents one from building a
> > Morrison-style "network" from Unix processes and pipes, though it's
> > hard to see how that would work without something like `select`, which
> > didn't yet exist in 1978. Regardless, Unix still doesn't expose a
> > particularly convenient syntax for expressing these sorts of
> > constructions at the shell.
>
> Process substitution is about as close as we can get, but most programs
> still process their filename arguments one at a time, beginning to end.
>
> The canonical process substitution example is
>
> 	diff <(old-program-version) <(new-program-version)
>
> to do simple regression testing.

And fanout is simply

	... | tee >(pipeline1) >(pipeline2)

Arnold