+ Created docker image with (NOTE ONLY lowercase in image tag) ...

  sudo docker build -f Dockerfiles/Dockerfile-gdiff-test -t pmur002/gdiff-test .

+ To test image interactively 
  (which is useful for testing that various things will run and installing
   packages interactively before adding them to the Dockerfile) ...

  sudo docker run -v $(pwd):/home/work/ -w /home/work --rm -t -i pmur002/gdiff-test /bin/bash

+ To make image available on DockerHub ...

  sudo docker login
  sudo docker push pmur002/gdiff-test