bash script that curls a url every minute and outputs audio if a regex doesn't match

appt.sh

check_for_opening () {
  res=`curl --silent "https://unionpt.fullslate.com/employees/4320?iid=7959&services%5B%5D=208" | grep "Next opening"`

  if [ -n "`echo $res | grep -e '.*Thursday, September 5.*'`" ]
  then
    echo "No openings found, sleeping..."
  else
    say "Found an appointment opening"
  fi
}

while true; do
  check_for_opening
  sleep 60
done