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Date:      Mon, 27 Mar 2000 17:40:23 +0100
From:      J McKitrick <jcm@freebsd-uk.eu.org>
To:        James FitzGibbon <james@targetnet.com>
Cc:        questions@freebsd.org
Subject:   Re: writing scripts
Message-ID:  <20000327174023.C10268@dogma.freebsd-uk.eu.org>
In-Reply-To: <20000327104539.A40393@targetnet.com>; from james@targetnet.com on Mon, Mar 27, 2000 at 10:45:39AM -0500
References:  <20000327160911.C9691@dogma.freebsd-uk.eu.org> <20000327104539.A40393@targetnet.com>

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On Mon, Mar 27, 2000 at 10:45:39AM -0500, James FitzGibbon wrote:
> A better way to accomplish this task is
> 
> grep -q search_string input_file
> retval=$?
> if [ $retval -eq 0 ]
> then
> 	... actions if found
> else
> 	... actions if not found
> fi
> 
> -q makes grep not produce output but exit with an error value based on
> whether the search string was found (0 if it was, something else if it was
> not).  The assignment of $? (the error value) to 'retval' is not technically
> required, but since $? changes with every external command that is run, it
> is a common mistake to insert commands between the grep and the test, thus
> changing the context of the test.  Assiging the error value to retval right
> after running the command preserves the value for later use.
> 
Perfect!  That's just what i needed.  I changed some of the test
conditions a little, but i think it will work.  I'lll let you know
when i telnet in from the other box.


Actuially, is there a way to tell whether the computer running telnet
or ssh is running windows or BSD?  That's really an even better
condition.  The BSD xterm and the tera-term terminal both have
different characteristics for showing color.  


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