if [ -z "$2" ]

echo "Usage: $0 img1 img2"

echo ""

echo "Example: $0 alpine:3.4 alpine:3.5"

exit 99

tmpdir=$(mktemp -d)

IMAGE_A=$1

IMAGE_B=$2

CONTAINER_A_ID=$(docker create $IMAGE_A /bin/sh)

CONTAINER_B_ID=$(docker create $IMAGE_B /bin/sh)

set -e

docker export "${CONTAINER_A_ID}" > ${tmpdir}/A.tar

docker export "${CONTAINER_B_ID}" > ${tmpdir}/B.tar

mkdir -p ${tmpdir}/${IMAGE_A} && tar -xf ${tmpdir}/A.tar -C ${tmpdir}/${IMAGE_A} --exclude='./etc/mtab' --exclude='./proc' --exclude='./dev'

mkdir -p ${tmpdir}/${IMAGE_B} && tar -xf ${tmpdir}/B.tar -C ${tmpdir}/${IMAGE_B} --exclude='./etc/mtab' --exclude='./proc' --exclude='./dev'

(

cd ${tmpdir}

diff --unified -arq ${IMAGE_A} ${IMAGE_B} 2>&1 | grep -v "No such file or directory" | grep -v "is a character special file" | grep -v "is a block special file" | tee ${tmpdir}/diff

)

cat ${tmpdir}/diff | wc -l > ${tmpdir}/difflinecount

set +e

code=1

if [ "$(echo `cat ${tmpdir}/difflinecount`)" = "0" ]; then

code=0

rm -rf ${tmpdir}

docker rm -fv "${CONTAINER_A_ID}" "${CONTAINER_B_ID}" > /dev/null

exit $code