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Date: Tue, 29 May 2007 21:42:10 -0600
From: Eric Blake <ebb9 AT byu DOT net>
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To: cygwin AT cygwin DOT com, binkley AT alumni DOT rice DOT edu
Subject: Re: more on Re: bash process substitution "<(list)" [spot the difference]
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According to B. K. Oxley (binkley) on 5/29/2007 9:05 PM:
> Why does one of these scripts produce an error and the other does not?
> function f()
> {
>    echo "$1"

shell builtin, and it does not touch the fifo (try replacing this with
/bin/echo to see the difference)

>    cat "$1"

so the fifo is still available

> function f()
> {
>    ls -l "$1"

external process, which calls exit() and thus closes the only read handle
on the fifo.  At which point, the writer is closed since no reader exists.

>    cat "$1"

the fifo no longer exists, so the error is correct

If you need the fifo to persist over several external commands, you need
to use a shell grouping construct or an exec so that the shell holds a
handle to the fifo for the duration of the shell function.  And this is
not cygwin specific.

- --
Don't work too hard, make some time for fun as well!

Eric Blake             ebb9 AT byu DOT net
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