From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <531b9b8ab78014b01db61629fece8281@plan9.escet.urjc.es>
To: 9fans@cse.psu.edu
Subject: Re: [9fans] rc - how to...
From: Fco.J.Ballesteros <nemo@plan9.escet.urjc.es>
MIME-Version: 1.0
Content-Type: multipart/mixed;
	boundary="upas-youonngozjkdotqebefbgrnkug"
Date: Fri, 13 Sep 2002 10:01:50 +0200
Topicbox-Message-UUID: e974e66a-eaca-11e9-9e20-41e7f4b1d025

This is a multi-part message in MIME format.
--upas-youonngozjkdotqebefbgrnkug
Content-Disposition: inline
Content-Type: text/plain; charset="US-ASCII"
Content-Transfer-Encoding: 7bit

Most of the times I wanted to do "while read { x }" I could
rewrite it to be "sed 's/^/x /' | rc", which works like a charm.

--upas-youonngozjkdotqebefbgrnkug
Content-Type: message/rfc822
Content-Disposition: inline

Received: from mail.cse.psu.edu ([130.203.4.6]) by aquamar; Thu Sep 12 16:35:21 MDT 2002
Received: from psuvax1.cse.psu.edu (psuvax1.cse.psu.edu [130.203.8.6])
	by mail.cse.psu.edu (CSE Mail Server) with ESMTP
	id DF5011999B; Thu, 12 Sep 2002 10:35:09 -0400 (EDT)
Delivered-To: 9fans@cse.psu.edu
Received: from doppio.vitanuova.com (unknown [62.254.170.97])
	by mail.cse.psu.edu (CSE Mail Server) with SMTP id 1D431199EC
	for <9fans@cse.psu.edu>; Thu, 12 Sep 2002 10:34:34 -0400 (EDT)
Message-ID: <35d1a51a345858e759eea904502ce78e@vitanuova.com>
To: 9fans@cse.psu.edu
Subject: Re: [9fans] rc - how to...
From: rog@vitanuova.com
MIME-Version: 1.0
Content-Type: text/plain; charset="US-ASCII"
Content-Transfer-Encoding: 7bit
Sender: 9fans-admin@cse.psu.edu
Errors-To: 9fans-admin@cse.psu.edu
X-BeenThere: 9fans@cse.psu.edu
X-Mailman-Version: 2.0.11
Precedence: bulk
Reply-To: 9fans@cse.psu.edu
List-Id: Fans of the OS Plan 9 from Bell Labs <9fans.cse.psu.edu>
List-Archive: <https://lists.cse.psu.edu/archives/9fans/>
Date: Thu, 12 Sep 2002 15:42:38 +0100

> du / | while(file=`{read})
> 	echo $file

it's probably worth mentioning that this is really quite slow, as the
read command is unable to do any IO buffering, must read one
character at a time, and is reloaded on every line of input:

on my machine,
	while (file=`{read}) {}

exececutes about 85 lines a second, whereas a simple xargs-like
program processes about 4300.

this could be quite significant if you're using to process
output from du (what was viable in the old bourne
shell with

	du . | while read x
	do something with $x
	done

is not necessarily fast enough in the rc equivalent)

--upas-youonngozjkdotqebefbgrnkug--