Save / Persist docker containers (with data):
Difference between # Docker save (image) and # Docker export (container)

Docker commands official documentation:
# man docker

Docker storage:
How is data stored in Docker

List images
$ sudo docker images
List containers (-a shows not running containers as well)
$ sudo docker ps -a

Delete container
$ sudo docker rm 665b4a1e17b6
Delete image
$ sudo docker rmi busybox

Run shell on an image
$ sudo docker run -it image_name /bin/bash

(assuming container is already created)
$ sudo docker start 665b4a1e17b6

$ sudo docker exec -i -t 665b4a1e17b6 /bin/bash #by ID
$ sudo docker exec -i -t loving_heisenberg /bin/bash #by Name

Alternative (only 1 possible shell instance):
$ sudo docker attach 665b4a1e17b6 #by ID
$ sudo docker attach loving_heisenberg #by Name

Export to a .tar file
$ sudo docker export <CONTAINER ID> > /home/export.tar
Import a .tar file
$ cat /home/export.tar | sudo docker import - busybox-1-export:latest

Save image to a .tar file
$ sudo docker save busybox-1 > /home/save.tar
Load image from a .tar file
$ docker load < /home/save.tar