delete-old-backups.sh

#!/bin/bash
#
# Pre-requesite is that GNU linux findutils package is installed (brew install findutils) for gfind
# Should be possible to just use find but I have not tested it (should just omit -daystart)
#
BACKUP_LOCATION=$(tmutil machinedirectory)
#MACHINE_NAME=$(scutil --get ComputerName)
DAY_AGE=30

if [ ! -d "${BACKUP_LOCATION}" ]; then
	echo "${BACKUP_LOCATION} is currently not accessible. Please connect your Time Machine disk or change the path."
	exit
fi

echo "*-* Removing old Time Machine Backups for ${MACHINE_NAME} older than ${DAY_AGE} days *-*"
# Get a list of all the backups in reverse order
result=$(gfind "${BACKUP_LOCATION}"/ -daystart -maxdepth 1 -mindepth 1 -mmin +$((60*24*${DAY_AGE})) | tail -r)

echo "$result"

if [ -n "$result" ]; then
	while read -r line; do
		START_TIME=$(date +%s)
		tmutil delete "$line"
		END_TIME=$(date +%s)
		echo "Elapsed time: $(($END_TIME - $START_TIME)) secs."
	done <<< "$result"

	echo "Finished!"
else
	echo "Did not find any Time Machine Backups older than ${DAY_AGE} days old."
fi