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

[Chet Ramey via TUHS]

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.

-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
		 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet at case.edu    http://tiswww.cwru.edu/~chet/
-------------- next part --------------
A non-text attachment was scrubbed...
Name: OpenPGP_signature.asc
Type: application/pgp-signature
Size: 203 bytes
Desc: OpenPGP digital signature
URL: <http://www.tuhs.org/pipermail/tuhs/attachments/20241205/5512f69a/attachment.sig>