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Groups > gnu.bash.bug > #16474

Re: Undocumented feature: Unnamed fifo '<(:)'

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From Robert Elz <kre@munnari.OZ.AU>
Newsgroups gnu.bash.bug
Subject Re: Undocumented feature: Unnamed fifo '<(:)'
Date Mon, 29 Jun 2020 03:21:22 +0700
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    Date:        Sun, 28 Jun 2020 12:06:10 -0400
    From:        Eli Schwartz <eschwartz@archlinux.org>
    Message-ID:  <d1172623-25cb-bcf9-b9b5-b7bf3cb547f7@archlinux.org>


  | You COMPLETELY failed to even read the reporter's message, which
  | specifically stated "In order to reduce forks and make some tasks a lot
  | quicker [...]"

I noticed that explanation, but like Dennis, I fail to see how the
complicated version does any more than pretend there are less forks
happening.   Was the speed of this actually measured, and if so, where
are the comparative results?

Either way, to make the conversion, the date command needs to be run
(in the complicated version, setbuf as well, which means an extra exec
at least) - running a command means a fork, and all we have to start
with is bash, so bash needs to fork to run date, each time it needs
to run.

What evidence is there that the complicated way, with all of its extra
file opens, etc, is faster than the simple way, or involves less forks?

kre

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Re: Undocumented feature: Unnamed fifo '<(:)' Robert Elz <kre@munnari.OZ.AU> - 2020-06-29 03:21 +0700

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