From mboxrd@z Thu Jan  1 00:00:00 1970
From: rogpeppe@gmail.com (roger peppe)
Date: Mon,  4 Apr 2011 10:26:39 +0100
Subject: [9fans] Making read(1) an rc(1) builtin?
In-Reply-To: <5ddd9deccbea5e8556dfc0c228b63311@ladd.quanstro.net>
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	<5ddd9deccbea5e8556dfc0c228b63311@ladd.quanstro.net>
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On 4 April 2011 03:53, erik quanstrom <quanstro at quanstro.net> wrote:
> i think this is what you want
>
> ? ? ? ?for(line in `{ifs=$nl cat}){...}

no, because that only sets ifs for the cat command, not
for the `{} construct.

ifs=$nl for (line in `{cat}) { ... }

is perhaps what you meant to say.

> but i have no idea why one would avoid the read
> idiom. ?for large input, forking off a read for each
> line keeps the memory footprint O(1).

FWIW, i think that avoiding a read(1) loop is
perfectly reasonable thing to want to do.

a quick test i measured that calling read in
shell loop was about 100 times slower than
using `{}, and about 500 times slower than
using awk to read the lines.

in general, unless it was truly necessary, i would
try to use awk or sed rather than use read(1) in
a loop when i was going to deal with significantly
sized input.

when i've needed a "-n safe" version of echo in
the past, i've used something like this:

fn myecho {echo -n $"* ^ '
'}