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Date: Wed, 29 Aug 2007 08:42:34 -0500
From: Reid Linnemann <lreid@cs.okstate.edu>
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To: Hinkie <Hinkie@paradise.net.nz>
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Cc: freebsd-questions@FreeBSD.ORG
Subject: Re: FreeBSD Cron Job to run (ifconfig em0 down; ifconfig em0 up)
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Written by Hinkie on 08/29/07 08:03>>
> Hi
> 
> I want to run a cron job in /etc/crontab that runs (ifconfig em0 down; ifconfig em0 up) if my cables static ip gateway can't be pinged but I can't figure it out.  I can't get the syntax that runs in the command window, to then put intot the crontab....
> 
> Can anyone help me?
> 
> I've tried all sorts such as:
> 
> if (ping -c1 a.b.c.1 != 1) then ifconfig em0 down; ifconfig em0 up endif
> 
> if ping -c1 a.b.c.1 != 1 then ping -c1 203.97.234.1 endif
> 
> if ping -c1 a.b.c.1 (ifconfig em0 down; ifconfig em0 up)
> 
> if ( ping -c1 a.b.c.1 != 1) ( ping -c1 203.97.234.182 )
> 
> if $command("=ping -c1 a.b.c.1 =0") echo sucess
> 
> if ping -c 1 -w 1 a.b.c.1 >/dev/null  echo sucess
> 
> if [[ (ping -q -c 3 a.b.c.1) == @(*100% packet loss*) ]]; echo sucess
> 
> if ! ping -c a.b.c.1 > /dev/null ; then echo sucess ; echo fail; fi
> 
> Any help would be appreciated.
> 
> Kind regards
> David Hingston 
> 

I would recommend you make a shell script, place it in /root/bin or 
something else sensible, and have cron call that. I think it's generally 
frowned upon to have excessive scripting directly in the crontab. The 
following script should do what you want:

#!/bin/sh
if ! ping -c1 203.97.234.1821>/dev/null 2>/dev/null
   then ifconfig em0 down && ifconfig em0 up
fi