Bash script to wait for time machine backup to finish, unmount drive, and shutdown

backoff.sh

#!/bin/bash

# Requesting sudo if we don't have it already
[ "$UID" -eq 0 ] || exec sudo bash "$0" "$@"

if [[ -z "$1" ]]; then
  #Replace this with your default harddrive (list them all with "df -h")
	hd="/Volumes/Harddrive";
else
	hd=$1;
fi
while ( ps -acx | grep 'backupd$' ); do
	echo "Still backing up";
	#A minute before we check again
	sleep 60;
done;
echo "done";
diskutil unmount "$hd";
#This loop shouldnt actually be needed but just to be safe..
while ( df -h | grep "$hd" ); do
	echo "Still connected";
	sleep 60;
done;
#Waits a minute to shutdown just in case
shutdown -h +1;