Install Docker on Ubuntu

sudo apt update
 
sudo apt install apt-transport-https ca-certificates curl software-properties-common

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu focal stable"
apt-cache policy docker-ce
apt install docker-ce

List images

docker image list

Run a container from an image

docker run --name <RUN_NAME> -p <HOST_PORT>:<CONTAINER_PORT> <IMAGE_NAME>:latest

List running containers

docker ps

Build a container

docker build -t <IMAGE_NAME> <DIR_OF_Dockerfile>

Upload an image to Docker registry

docker push <IMAGE_NAME>

Save (export) an image

docker save <IMAGE_NAME>:latest -o image.tar

Save (export) an image with real-time gziping

docker save <IMAGE_NAME>:latest | gzip > image.tgz

Fix unsigned repo errors for ubuntu and debian

docker system prune

Delete all local images

docker rmi -f $(docker images -aq)