sleep 50m
while true; do
  H="`date +%H`"
  if [ "$H" -ge 23 -o "$H" -lt 6 ]; then
#    sudo sh -c 'chvt 1; (clear ; echo "It is `date +%l:%M` - time to finish up!") > /dev/tty1'
#    xmessage -geometry -0-0 "It's `date +%l:%M` - time to finish up!"
#    sudo chvt 1
#    sudo clear >/dev/tty1 
#    sudo echo >/dev/tty1 "It's `date +%l:%M` - CURFEW!  STOP WITHIN 5 MINUTES!!!"
    alert "It's `date +%l:%M` - LATE!! - time to finish up!"
    sleep 30m
  elif [ "$H" -ge 20 ]; then
#    sudo sh -c 'chvt 1; (clear ; echo "It is `date +%l:%M` - time to finish up!") > /dev/tty1'
#    xmessage -geometry -0-0 "It's `date +%l:%M` - time to finish up!"
    alert "It's `date +%l:%M` - time to finish up!"
    sleep 30m
  else
#    sudo sh -c 'chvt 1; (clear ; echo "Take a 10 minute break, exercise, get a drink of water.") > /dev/tty1'
#    xmessage -geometry -0-0 "Take a 10 minute break, exercise, get a drink of water."
    alert "Take a 10 minute break, exercise, get a drink of water."
    sleep 70m
  fi
done