From mboxrd@z Thu Jan  1 00:00:00 1970
From: 9p-st@imu.li (Tristan Plumb)
Date: Sun,  3 Apr 2011 19:41:05 -0400
Subject: [9fans] Making read(1) an rc(1) builtin?
In-Reply-To: <86fwpz55nj.fsf@cmarib.ramside>
References: <86fwpz55nj.fsf@cmarib.ramside>
Message-ID: <257867.782e4d7b.wsc0.mx@tumtum.plumbweb.net>
Topicbox-Message-UUID: c7424edc-ead6-11e9-9d60-3106f5b1d025

> One thing that has come to concern me about rc(1) is that read(1) is
> not a "builtin" command.

The general idea here is that forking a new process is not usually
(ever?) the bottleneck, if you have a script that needs to run faster,
there's other overhead to trim first, and if you really need to, you can:
(giving up line at a time response).

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

There isn't any such trick (that I know) for test, but how much is it
slowing you down?

> I'm also a bit stumped by the fact that rc(1) doesn't have anything
> analogous to bash(1)'s string parsing operations: ${foo#bar},
> ${foo##bar}, ${foo%bar}, ${foo%%bar}, or ${foo/bar/baz}.
I could never remember what these did, except the last one.

> Is there any way to extract substrings (or single characters) from a
> string in rc(1) without having to fork a dd, awk, or sed?
Sure, for some things, except it uses cat! Without any forking, I don't
know (see below).

On the other hand, echo -n is a wart. I wonder, does echo '' -n work?
(My plan9 machine is off and far away.)

On a more friendly note. Hi, I think I know you slightly, telephones.

Tristan

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