bridge-interface-hotswap-detect.sh

#!/bin/bash
interfaces=(eth0 eth1 eth2) # which interfaces to auto-detect, in descending order of priority
interface="eth0" # the default/current interface

while true; do
  newif="$interface"
  for i in "${interfaces[@]}"; do 
    if $(ip link show dev "$i"); then
      newif="$i"
    fi
  done
  if [[ ! "$interface" == "$newif" ]]; then
    echo "Switching from $interface to $newif"
    brctl delif br0 "$interface" || true
    brctl addif br0 "$newif"
    interface="$newif"
  fi
  sleep 5
done