Restore docker image tag from text file.

restore_docker_image_tag.sh

# 1. Backup image tags to text file.
#    $ docker images --format "{{.Repository}}:{{.Tag}} {{.ID}}" > img_id.txt
#
# 2. Execute clean-docker-for-mac script
#    $ bash clean-docker-for-mac.sh $(docker images --format "{{.ID}}" | xargs)
#
#    source: https://gist.github.com/MrTrustor/e690ba75cefe844086f5e7da909b35ce#file-clean-docker-for-mac-sh 
#
# 3. Execute this script to restore tags from text file.

#!/bin/bash

filename='img_id.txt'
exec < $filename

while IFS=' ' read -r col1 col2
do
      echo 'repo:' $col1
      echo 'tag': $col2
      docker tag $col2 $col1
done