MacBatteryUsage.sh

#!/bin/bash
while true
do
  OUT=`/usr/bin/pmset -g batt`
  PERCENTLEFT=`echo $OUT | awk '{print $8}' | sed 's/%;//'`
  if [ ${PERCENTLEFT} \< 40 ];
    then
    echo "${PERCENTLEFT} percent battery left" > /tmp/batterywarning
  fi

  if [ -f /tmp/batterywarning ];
    then
    say -v 'Tessa' -f /tmp/batterywarning
    rm -f /tmp/batterywarning
  fi
sleep 60
done