Watch a Web page for changes and show the differences

watch_page

#!/bin/bash

# usage:
# chmod +x watch_page
# ./watch_page

while [ 1 ]
do
  if [ -e /tmp/latest.html ]; then
    cp /tmp/latest.html /tmp/previous.html
  else
    touch /tmp/previous.html
  fi

  curl -s https://www.drudgereport.com/ > /tmp/latest.html

  new=`shasum /tmp/latest.html | awk '{ print $1 }'`
  old=`shasum /tmp/previous.html | awk '{ print $1 }'`

  if [ "$new" != "$old" ]; then
    echo "Page has changed:"
    diff /tmp/previous.html /tmp/latest.html
    echo "----------------------"
  else
    echo "Page has not updated"
  fi

  echo "Sleeping.. ctrl+c to quit, enter to retry"
  read -t 120
done