dhcp - How to configure `eth0` to retry `dhclient` when unplugged and replugged?

I'm working on a linux gadget.

I want it to get DHCP if I plug in the network cable after it has booted up already or if the network cable unplugged and replugged.

One solution is to run a script such as this (which works, btw):

#!/bin/bash

NET_STATUS='different'

while true
do
  NEW_NET_STATUS=`ifconfig | grep RUNNING | grep -v LOOPBACK`
  if [ "${NEW_NET_STATUS}" = "${NET_STATUS}" ]
  then
    echo "no change"
    sleep 1
    continue
  fi
  NET_STATUS=${NEW_NET_STATUS}
  if [ "${NET_STATUS}" ]
  then
    echo "cable plugged in"
  else
    echo "cable unplugged"
  fi
  sleep 1
done

However, I've got a feeling deep down in my little toe that tells me that there's a better way to deal with hotplug events for the ethernet cable.

Answer

netplug is the solution that I went with. ifplugd may work just as well.

Installation

sudo apt-get install netplug

Interface Configuration

cat /etc/netplug/netplugd.conf
eth*

Event Configuration

cat /etc/netplug/netplug
#!/bin/sh
PATH=/usr/bin:/bin:/usr/sbin:/sbin
export PATH

dev="$1"
action="$2"

case "$action" in
in)
    echo "$dev : $action : plugged in" >> /tmp/netplug.log
    ;;
out)
    echo "$dev : $action : unplugged" >> /tmp/netplug.log
    ;;
probe)
    echo "$dev : $action : probed" >> /tmp/netplug.log
    ;;
*)
    echo "$dev : $action : I feel violated" >> /tmp/netplug.log
    exit 1
    ;;
esac

Testing

/etc/init.d/netplug stop
/etc/init.d/netplug start

cat /tmp/netplug.log
eth0 : probe : probed
eth1 : probe : probed
...
eth15 : probe : probed
eth0 : in : plugged in