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

[John Levine]

According to Dan Cross <crossd at gmail.com>:
>> >       diff <(old-program-version) <(new-program-version)
>> >
>> > to do simple regression testing.
>>
>> And fanout is simply
>>
>>         ... | tee >(pipeline1) >(pipeline2)
>
>And indeed these things are pretty nifty, but don't they generate
>trees, and not arbitrary dags? They don't quite capture the full
>generality of Morrison-style networks since it doesn't seem like
>there's a way to connect process substitution fan-out with fan-in; at
>least, not conveniently.

You can use mkfifo to make named pipes and then plumb them as wanted.  It's
not particularly beautiful but it's as general as you could want.

That's worked since 4.4BSD which was quite a while ago.