A way to install docker on a ubuntu system

install_docker_on_ubuntu

# Uninstall Docker
sudo apt-get remove docker docker-engine docker-ce docker.io

# Update the apt package index
sudo apt-get update

# Allow apt to use a repository over HTTPS
sudo apt-get install \
    apt-transport-https \
    ca-certificates \
    curl \
    software-properties-common

# Add Docker’s official GPG key to apt
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -

# Verify that you now have the Docker GPG key
sudo apt-key fingerprint 0EBFCD88

# Add the Docker repository to apt
sudo add-apt-repository \
   "deb [arch=amd64] https://download.docker.com/linux/ubuntu \
   $(lsb_release -cs) \
   stable"

# Re-Update the apt package index now that we have the Docker repositories added
sudo apt-get update

# Install a specific version of Docker
sudo apt-get install docker-ce=17.12.0~ce-0~ubuntu

# Make sure that the Docker group is already added
sudo groupadd docker

# Add your username to the Docker group
sudo usermod -aG docker $USER

# Log out and back in

# Test Docker with the version command and hello-world
docker version
docker run hello-world