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From: j@uriah.heep.sax.de (J Wunsch)
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Re: sh command shell script writing. i'm stuck
Date: 9 Aug 1996 06:46:30 GMT
Organization: Private BSD site, Dresden
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Message-ID: <4uems6$2mm@uriah.heep.sax.de>
References: <4t02d1$nec@cliff.island.net>
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Reply-To: joerg_wunsch@uriah.heep.sax.de (Joerg Wunsch)
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brian@awfulhak.demon.co.uk (Brian Somers) wrote:
> With zsh
> (I'm told) and ksh (not pdksh), the following is even better:
>
> x=1
> while read line
> do
> test $x -eq TheNumberIWant && {
> echo $line
> break
> }
> done <input_file
This should even work with a plain Bourne shell. while loops are
always treated as subshells, and can get separate IO redirection. You
can also pipe into a while loop:
grep foobar mumble | awk '{print $1 " " $3}' | while read f1 f2
do
do something with $f1 and $f2
done
Loops of this kind allowed me to install 386BSD off the two dozen
floppies on a machine that did not have the disk space to hold a
temporary copy of the installation files... (with prompting for the
next floppy inside the loop etc.).
;-)
--
cheers, J"org
joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE
Never trust an operating system you don't have sources for. ;-)