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Groups > gnu.bash.bug > #14273

Re: Directing into a variable doesn't work

From Robert Elz <kre@munnari.OZ.AU>
Newsgroups gnu.bash.bug
Subject Re: Directing into a variable doesn't work
Date 2018-06-25 00:27 +0700
Message-ID <mailman.2503.1529861302.1292.bug-bash@gnu.org> (permalink)
References <f2371578-5dfe-93f5-b242-1fa5b9ffa7f9@passchier.net> <634e501a-5db1-d9ae-ae0b-bb3b414a2def@passchier.net> <acc5bff9-868a-31be-7439-c014fc517122@inlv.org>

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    Date:        Sun, 24 Jun 2018 22:26:52 +0700
    From:        Peter Passchier <peter@passchier.net>
    Message-ID:  <f2371578-5dfe-93f5-b242-1fa5b9ffa7f9@passchier.net>

  | I am surprised by the general internal usage of temporary files for
  | here-documents & here-strings, because (generally speaking) memory is
  | quite abundant,

That's not the real issue - rather it is that a here doc is presented to the
command beng run as a file descrptior - that command will want to do a
read() to obtain the data.  Simply sitting in memory doesn't help, that
memory isn't available to the command that is being run - it needs to be
in a file, or sent through a pipe.   The file method is more general, as it
also allows mmap(), and is much easier to write the code to avoid issues
when there is more than one here doc for the same command - so the
data needs to be available to both in whatever order the command wants it.

Much the same arguments would apply to output.

kre

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Re: Directing into a variable doesn't work Robert Elz <kre@munnari.OZ.AU> - 2018-06-25 00:27 +0700

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