Bash scripting help...

[Jacques B.]

On 8/7/06, list user <xktnniuymlla at mailinator.com> wrote:
> Marko Vojinovic wrote:
> > I am writing a bash script to discover a MAC address of a remote host based on
> > it's IP. Found that arping might be useful (is there a better method?), so I
> > get
> >
> > # arping -f -I eth0 $ipnumber
> > ARPING 10.0.0.3 from 10.0.0.1 eth0
> > Unicast reply from 10.0.0.3 [00:0C:29:C8:DE:E2]  1.040ms
> > Sent 1 probes (1 broadcast(s))
> > Received 1 response(s)
> >
> > but the problem is that I just need to set the variable, say macaddr, to the
> > above value, hopefully lowercase, without the [ and ]. Next obvious thing
> > was:
> >
> > # arping -f -I eth0 $ipnumber | grep Unicast
> > Unicast reply from 10.0.0.3 [00:0C:29:C8:DE:E2]  1.040ms
> >

This worked at the command line when I tested it:

$ ip=$(/sbin/arping -f -I eth0 10.255.255.1 | grep Unicast | awk
'{print $5}' | sed 's/\[/ /' | sed 's/\]/ /');echo $ip

So in a script remove the last command ";echo $ip" (and the bash $
prompt at the beginning is just that, a prompt) and you are in
business.

Jacques B.