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Date: Wed, 29 Aug 2007 21:54:51 +0300
From: Giorgos Keramidas <keramida@ceid.upatras.gr>
To: Wojciech Puchar <wojtek@wojtek.tensor.gdynia.pl>
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Cc: freebsd-questions@freebsd.org, Hinkie <Hinkie@paradise.net.nz>
Subject: Re: FreeBSD Cron Job to run (ifconfig em0 down; ifconfig em0 up)
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On 2007-08-29 18:51, Wojciech Puchar <wojtek@wojtek.tensor.gdynia.pl> wrote:
> fragment from my test program (used for other thing but doesn't matter)
>
> /sbin/ping -i 0.5 -s 1450 -c 3 tested_host >/dev/null 2>/dev/null
> if [ $? != 0 ];then
>   perform_action_if_doesnt_ping
> fi

I'm not sure if '!=' is a 'portable' way to write sh(1) tests,
but you have a point there :-)

Rewriting this as:

        #!/bin/sh

        ping -i 0.5 -s 1450 -c 3 tested_host >/dev/null 2>&1
        if test $? -eq 0 ; then
                exit 0
        fi

        perform_action_if_doesnt_ping

may save you an extra indentation level too.