Subject: Re: "yes" curiousity
To: None <port-alpha@netbsd.org>
From: der Mouse <mouse@Rodents.Montreal.QC.CA>
List: port-alpha
Date: 06/23/1999 00:55:47
> [...], I went ahead and typed "yes".
> That brings me full circle to my original thought...that seems
> awfully stupid.
It is, as you discovered. About as useful as typing "cat".
Okay, but seriously... :-)
I've yet to see anyone provide a non-contrived use of "yes".
So, let me do so. This is a real script, in real use, created to fill
a real need. The idea is to try to catch media errors on new tapes by
writing them to EOT with junk. As the tapes are about 4 gig long, it's
no practical to just have a single file which gets dumped to the tape.
Here's the script. All you need to know about catblock is that it
copies its input to its output in a certain way, and does something
useful when sent SIGUSR1.
#! /bin/sh
PATH=/home/shamash/mouse/sun4/hacks:$PATH
export PATH
cd /home/shamash/mouse/sun4/tmp
junkfile=junk.10M
case $# in
1) ;;
*) echo Usage: $0 config-name 1>&2
exit 1
;;
esac
config="$1"
( exec 3>&1
yes cat\ $junkfile |
sh -e |
sh -c 'echo $$ 1>&3; exec catblock -c 32768' \
> /local/backup/dev/$config/dev 2> junk-log.$config
) | ( read pid; sleep 10; while kill -USR1 $pid; do sleep 300; done )
der Mouse
mouse@rodents.montreal.qc.ca
7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B