add-apt-repository on docker code example

Example 1: how to install docker ubuntu

sudo apt-get update
sudo apt-get upgrade
sudo apt install docker.io
systemctl start docker
systemctl enable docker
docker --version

Example 2: get-docker sh

curl -fsSL https://get.docker.com -o get-docker.sh

Example 3: how to install docker on ubuntu

sudo apt install docker.io