Delete all untagged images and - optionally - images from specified {repository} if older than {max-age}

cleanup_docker.sh

#!/bin/bash
#
# Usage:
#   $ cleanup_docker.sh [repository max-age]

echo "Deleting untagged images...."
UNTAGGED_IMAGES=$(docker images | grep "^<none>" | awk '{print $3}')
if [ ! -z "$UNTAGGED_IMAGES" ]; then
    docker rmi $UNTAGGED_IMAGES
else
    echo "No untagged images found."
fi

if [ ! -z "$1" ]; then
    IMAGE_NAME="$1"
    if [ ! -z "$2" ]; then
        TS_LIMIT=$(date '+%s' --date="$2")
        if [[ $? -gt 0 ]]; then
            exit 1
        fi
        echo "Deleting images matching '$IMAGE_NAME' older than $(date -Iminutes -d "@$TS_LIMIT")"

        MATCHING_IMAGES="$(docker images --format '{{.Repository}},{{.ID}}' | grep "^$IMAGE_NAME")"
        IFS=$'\n'
        for row in $MATCHING_IMAGES; do
            IMAGE_ID="$(echo "$row" | awk -F',' '{print $2}')"
            IMAGE_DATE_UTC="$(docker inspect -f "{{.Created}}" $IMAGE_ID)"
            IMAGE_TS=$(date '+%s' --date="$IMAGE_DATE_UTC")
            if [[ "$IMAGE_TS" -lt "$TS_LIMIT" ]]; then
                echo "* Deleting $IMAGE_ID ($IMAGE_DATE_UTC)"
                docker rmi -f $IMAGE_ID
            fi
        done
    fi
fi