My macbook air is getting old, so the battery is rather unreliable. This means I have to keep it constantly charged, or my computer may shut down suddenly as the battery plummets. But the charger is also old, and so sometimes if i shift the computer around it disconnects suddenly without my knowledge. Is there a way to set an audio alarm for when the computer disconnects from the charger? The only solutions online i found are for when the battery gets low, which may not occur because the battery drops and raises its percentage without warning, or unavailable in singapore.


1 Answer 1


This can be done by using the pmset -g batt command. The first line of output from this command indicates your power source, e.g.:

Now drawing from 'AC Power'


Now drawing from 'Battery Power'

A possible use for this might be to change various commands together in a batch file, e.g.:

pmset -g batt | head -n 1 | grep "Battery"

In the above example, you'll only get output when you're running on battery power. So, a reasonable approach might be to use a bash script running via launchd or as a hidden Login Item in your profile. Something like this would work a charm:

while true; do
  if $(pmset -g batt | head -n 1 | grep -q "Battery"); then
      say "Running on battery";
      sleep 5;
sleep 5;

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