Well, other than standard error and standard out, yeah, it would be nice
to have more than 2 streams per program. ;-)
On the other hand, most programs don't do much more than give one output
stream anyway, so you're going to have to 'go back and run another
pipeline' regardless. Of course, if you're ending up writing a script
(assuming you're going to do this more than a few times), its not quite
such an issue, personally. I suppose you could get really silly and
send to multiple IPC pipelines, or maybe receive from multiple ones.
And on doing it all at the same time - yep, that's something I don't
think Windows ever has figured out how to do. (Remember back when you'd
format a floppy and basically lose the use of your computer until it was
done!? :-) They've improved it somewhat, sorta ;-)
On 12/25/22 18:16, David Schwartz via PLUG-discuss wrote:
Hi, Rusty.
Yes, I know about tee, but those pipes really only allow one flow.
I’ve used tee to save off a snapshot of the data at different points of the
process, but then you have to come back later and run another pipeline to
process each one separately.
I learned all of this stuff at Moto working on a Unix System V Rel III port to the
68020, and I was quite amazed that all of the commands in a pipe ran in parallel. I
could run the pipe in a bg process (with <ctrl>-Z) and then run top and see all
of the commands in the pipe running simultaneously.
When you do that in Windows, they’re totally synchronous: it’s like running one
command after another in a batch file, saving the results of one to a temp file
before passing it as input to the next command.
Running ‘man tee’ in a Mac shell says you can just send the output to a file.
It’s dated 1993, so clearly it hasn’t been updated in 30 years.
It would be nice to be able to run a command from a tee that implements a
separate pipeline, no?
-David Schwartz
On Dec 25, 2022, at 1:45 PM, Rusty Carruth via PLUG-discuss
<plug-discuss@lists.phxlinux.org> wrote:
Hi, David!
I'd like to respond to a single thought in your entire message. The message was
interesting, but I'm only going to tackle this one thing:
On 12/25/22 00:20, David Schwartz via PLUG-discuss wrote:
We saw it first employed in Unix systems with the command shell that lets you
create “pipes” by connecting various commands together. The command shell
implements a fairly simple language that’s hard to say is either imperative or
declarative. Some would argue it’s more of a functional language.
But you can see more contemporary evolutions of this approach in Zapier and
IFTTT.
The problem with this linear “pipeline” approach is that you have to have some
way to divert feeds off of the main data stream to drive displays, and that’s
not something we see implemented much. Usually the end of a Zapier “zap” goes
into some kind of rendering widget, or a spreadsheet or DB.
Anybody who’s tried to use a single Unix pipe command to display multiple views
of the data going through it knows this is one of it’s major weaknesses.
Well, yes, but I've used 'tee' to great effect here to grab off parts of the
flow of a pipe for later use. So you can grab views of the data as it flows,
but yes I'll agree command pipelines don't make it trivial.
Well, since I'm sending a message, I'll add "Merry Christmas to all, and to all a
good night!" ;-)
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