Based off of https://gist.github.com/mugli/f538e8fb0554267c1028068b75e17c59

anmeldung-termin-notifier.sh

#!/bin/bash

ROOT_URL="https://service.berlin.de/terminvereinbarung/termin"
FULL_URL="${ROOT_URL}/tag.php?termin=1&anliegen[]=120686&dienstleisterlist=122210,122217,122219,122227,122231,122243,122252,122260,122262,122254,122271,122273,122277,122291,122285,122286,122296,150230,122301,122297,122294,122312,122314,122304,122311,122309,122281,122279,122276,122274,122267,122246,122251,122257,122208,122226&herkunft=http%3A%2F%2Fservice.berlin.de%2Fdienstleistung%2F120686%2F"
DELAY_SEC=600

PATTERN="\"buchbar\""

function show_notification {
  osascript -e 'display notification "Termin available for Anmeldung!"'
}
counter=1

while true
do
  echo "Run number: $counter"
  slot_exists=`wget ${FULL_URL} -qO- | grep -c "${PATTERN}"`
  [[ $slot_exists -gt 0 ]] && show_notification && echo "$(date):    $slot_exists slots available now!"
  ((counter++))
  sleep ${DELAY_SEC}
done