From: Peter Stephenson <pws@pwstephenson.fsnet.co.uk>
To: zsh-workers@sunsite.auc.dk (Zsh hackers list)
Subject: Re: <> redirection operator
Date: Mon, 04 Jun 2001 00:14:00 +0100 [thread overview]
Message-ID: <20010603231405.92A4614285@pwstephenson.fsnet.co.uk> (raw)
In-Reply-To: "Clint Adams"'s message of "Sun, 03 Jun 2001 17:00:08 EDT." <20010603170008.A32165@dman.com>
(Sigh. After half a dozen years of the mailing list sending replies to the
original sender, I'm still forgetting to change the address.)
Clint Adams wrote:
> > All this means is that fd 0 is O_RDWR rather than O_RDONLY. It still
> > opens exactly one descriptor.
>
> Ah. What is the point of that?
To put it another way,
% echo test >/tmp/redirtest
% sed 's/e/Z/g' <>/tmp/redirtest 1>&0
% cat /tmp/redirtest
tZst
(This happens to work in place even on a mult-line file, but I think you
have to be pretty sure what you're doing to use it like that. Finally I've
got an example of this for the user guide, anyway.)
It's just consistently applying the rule that one redirection redirects
exactly one file descriptor, and to do the other you need to do it
explcitly as above.
--
Peter Stephenson <pws@pwstephenson.fsnet.co.uk>
Work: pws@csr.com
Web: http://www.pwstephenson.fsnet.co.uk
next prev parent reply other threads:[~2001-06-03 22:13 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-06-03 20:10 Clint Adams
2001-06-03 20:49 ` Bart Schaefer
2001-06-03 21:00 ` Clint Adams
2001-06-03 23:14 ` Peter Stephenson [this message]
2001-06-03 23:06 ` Bart Schaefer
[not found] <201112221539.pBMFdlaj011933@penguin.research.att.com>
2011-12-22 21:03 ` '>;' redirection operator [was: [1003.1(2008)/Issue 7 0000530]: Support in-place editing in sed (-iEXTENSION)] Eric Blake
2011-12-22 22:09 ` Bruce Korb
2011-12-22 23:34 ` '>;' redirection operator Thorsten Glaser
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