install ubuntu 18.04 in docker container 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: install docker in ubuntu
$ sudo apt-get remove docker docker-engine docker.io
$ sudo apt-get update
$ sudo apt install docker.io
$ sudo snap install docker
$ docker --version