From: Stephane Chazelas <stephane_chazelas@yahoo.fr>
To: Peter Stephenson <p.w.stephenson@ntlworld.com>
Cc: zsh-users@zsh.org
Subject: Re: {fd}< and compound commands
Date: Wed, 14 Sep 2011 20:31:41 +0100 [thread overview]
Message-ID: <20110914193141.GB7325@yahoo.fr> (raw)
In-Reply-To: <20110914200601.72c91f87@pws-pc.ntlworld.com>
2011-09-14 20:06:01 +0100, Peter Stephenson:
[...]
> {
> exec {fd}<file
>
> while read; do
> ...
> done <&$fd
> } always {
> exec {fd}<&-
> }
Thanks Peter,
Why the "always" here?
> (although in this particular case there's nothing to stop you doing
>
> while read var; do
> ...
> done <file
>
> but I presume you have something more complicated in mind.)
[...]
Well, using fd 0 here is dangerous as you never know if commands
in the loop will attempt to read from it (think of ssh without -n
for instance), or you may actually want them to read from (the
original) stdin.
--
Stephane
next prev parent reply other threads:[~2011-09-14 19:37 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-14 17:21 Stephane Chazelas
2011-09-14 17:36 ` Mikael Magnusson
2011-09-14 19:06 ` Peter Stephenson
2011-09-14 19:31 ` Stephane Chazelas [this message]
2011-09-14 21:05 ` Peter Stephenson
2011-09-15 12:58 ` Stephane Chazelas
2011-09-15 13:09 ` Peter Stephenson
2011-09-15 13:22 ` Chet Ramey
2011-09-15 14:21 ` Stephane Chazelas
2011-09-17 12:21 ` Stephane Chazelas
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