This tutorial is on how to delete a dangling image that cannot be deleted.
Command used in this demo.
1) Delete image
docker image rm IMAGE_NAME
2) Clear screen
clear
3) Directory list
ls
4) Make new directory
mkdir
5) Copy file
cp
6) Revision of Ubuntu
lsb_release -a
7) List docker image
docker image ls
8) List docker container
docker container ls
9) Prune/Delete all dangling containers
docker container prune