ping.sh

#!/bin/bash

HOST="some-host.com"
ERROR_MESSAGE="Some Host server unreachable!"

while true
do
  status=$(curl -s -I $HOST | grep HTTP/1.1 | awk {'print $2'})
  timestamp=$(date +"%Y-%m-%d %H:%M:%S")

  if [ $status = 200 ] || [ $status = 401 ]
  then
    echo "$timestamp -- OK"
  else
    echo "$timestamp -- $ERROR_MESSAGE"
    osascript -e "display notification \"$ERROR_MESSAGE\""
  fi

  sleep 60
done