Simple rudimentary script for Mac OS X which restarts Wifi if the network is unreachable. I need this script because my Mac doesn't work nice with my ISP's cable modem by Ubee.

mac_wifi_watchdog.sh

#!/bin/bash
#
# Restart Wifi if network connection doesn't respond.
# Usage: Open Terminal, and execute this script. 
#        Optimally you want to use a terminal multiplexer like screen to keep it running
#
while :
do
  ping -c 3 google.nl

  if [[ $? -ne 0 ]]; then
    osascript -e 'display notification "Could not ping google.nl, restarting Wifi connection" with title "Restarting Wifi" sound name "Submarine"'
    networksetup -setairportpower en0 off
    sleep 5
    networksetup -setairportpower en0 on
  fi
  sleep 5
done