This script installs automated docker cleanup via "docker image prune"

cleanup-docker.sh

#!/bin/sh
# This script installs automated docker cleanup via "docker image prune"
# onto systemd-based systems.
# It requires that docker is installed properly
# source: https://techoverflow.net/2019/10/03/how-to-automatically-cleanup-prune-docker-images-daily/

cat >/etc/systemd/system/PruneDocker.service <<EOF
[Unit]
Description=PruneDocker

[Service]
Type=oneshot
ExecStart=/usr/bin/docker system prune -a -f
WorkingDirectory=/tmp
EOF

cat >/etc/systemd/system/PruneDocker.timer <<EOF
[Unit]
Description=PruneDocker

[Timer]
OnBootSec=15min
OnCalendar=daily
Persistent=true

[Install]
WantedBy=timers.target
EOF

# Enable and start service
systemctl enable PruneDocker.timer && sudo systemctl start PruneDocker.timer