Watch a URL for updates and pop up a notification if it changes.

watch-page.sh

#!/bin/bash

URL=$1
LAST_PAGE="cache.html"

while true; do
    curl -s "$URL" > "$LAST_PAGE"
    echo -n "$(date) - $(stat -f "%z" "$LAST_PAGE") - "
    openssl md5 "$LAST_PAGE" | cut -d' ' -f2
    if ! diff -q "$LAST_PAGE" "$LAST_PAGE.old" > /dev/null; then
        osascript -e 'display notification "Page changed!" with title "Page changed!"'
    fi
    mv "$LAST_PAGE" "$LAST_PAGE.old"
    sleep 60
done