$ docker run -i -t ubuntu:12.04 /bin/bash
Without a name, just using the ID:
$ docker run -i -t 8dbd9e392a96 /bin/bash
docker exec -i -t <Container ID> /bin/bash
$ docker build -t "simple_flask:dockerfile" .
$ docker build -t nginx_image .
# From specific dockerfile
$ docker build -t "simple_flask:dockerfile" -f Dockerfile_test .