El Cheapo Internet Monitor

internet_monitor.rb

was_down = false

while true
  t = Time.now.strftime("%l:%M:%S%p")
  result = `ping -c 1 www.google.com 2>&1`
  if result !~ /1 packets received/
    puts "Check at #{t} -- DOWN!"
    if was_down
      #don't repeat the notification if we're still down
      `say "Internet down!"`
      ` growlnotify -a "Internet Monitor" -m "Internet Down at #{t}" -s -p Emergency `
    end
    was_down = true
  else
    puts "Check at #{t} -- ok"
    if was_down
      `say "Internet back online"`
      ` growlnotify -a "Internet Monitor" -m "Internet Back Up at #{t}" -s -p Emergency `
    end
    was_down = false
  end
  sleep 60 #adjust this to the number of seconds you want checks
end