Docker Prune Preview

mise.toml

# Add to your own config at ~/.config/mise/config.toml

[tasks."docker:prune-preview"]
description = "Dry-run of docker system prune: show what each prune flavour WOULD remove"
run = '''
{% raw %}
hr() { printf '\n\033[1m== %s\033[0m\n' "$1"; }

hr "STOPPED CONTAINERS (removed by: docker container/system prune)"
docker ps -a --filter status=exited --filter status=created \
  --format 'table {{.Names}}\t{{.Status}}\t{{.Image}}\t{{.Size}}'

hr "DANGLING IMAGES (removed by: docker image/system prune)"
docker images -f dangling=true

hr "IMAGES NOT USED BY ANY CONTAINER (additionally removed by: prune -a)"
USED=$(docker ps -aq | xargs -r docker inspect --format '{{.Image}}' | sort -u)
docker images --no-trunc --format '{{.ID}}\t{{.Repository}}:{{.Tag}}\t{{.Size}}' | \
  while IFS="$(printf '\t')" read -r id ref size; do
    case "$USED" in
      *"$id"*) ;;
      *) printf '%s\t%s\n' "$ref" "$size" ;;
    esac
  done | column -t

hr "DANGLING VOLUMES (removed by: prune --volumes — DATA LOSS territory)"
docker volume ls -f dangling=true

hr "BUILD CACHE (removed by: builder/system prune)"
docker builder du 2>/dev/null | tail -3

hr "RECLAIMABLE SUMMARY (docker system df)"
docker system df
{% endraw %}
'''