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From: Mike Meyer <mwm@mired.org>
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Date: Fri, 28 Sep 2001 14:11:17 -0500
To: Cliff Sarginson <cliff@raggedclown.net>
Cc: questions@freebsd.org, bsd-freak@mbox.com.au
Subject: Re: if then statement with grep
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Cliff Sarginson <cliff@raggedclown.net> types:
> On Tue, Sep 25, 2001 at 09:03:14PM -0500, Conrad Sabatier wrote:
> > 
> > On 26-Sep-2001 Edwin Groothuis wrote:
> > > On Wed, Sep 26, 2001 at 10:56:43AM +1000, BSD Freak wrote:
> > >> if `grep "expected line" /var/log/mylogfile` does NOT return something
> > >> then
> > >> mail -s "Alert" me@mycompany.com
> > >> otherwise don't bother me
> > > 
> > > if [ ! -z "`grep "expected line" /var/log/mylogfile`" ]; then
> > >       ... do your stuff here ...
> > > fi
> > Actually, a simple "if ! grep ..." should do the same thing.
> Or even
> 
> grep "expected line" /var/log/mylogfile >/dev/null
> [ $? -ne 0 ] && { echo "In this house we obey the laws of thermodynamics"; }

You can simplify even further if you ask grep nicely:

grep -q "expected line" /var/log/myfile" && echo KISS

This is even more efficient that the other solutions, as grep will
stop on the first match and exit with success.

	<mike
--
Mike Meyer <mwm@mired.org>			http://www.mired.org/home/mwm/
Q: How do you make the gods laugh?		A: Tell them your plans.

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