How To Install and Use Docker on Ubuntu 18.04

docker.sh

#Update your existing list of packages
sudo apt update

#Install a few prerequisite packages
sudo apt install apt-transport-https ca-certificates curl software-properties-common

#Add the GPG key for the official Docker repository
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -

#Add the Docker repository to APT sources
sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu bionic stable"

# Update the package database
sudo apt update

#Make sure to install from the Docker repo instead of the default Ubuntu repo
apt-cache policy docker-ce

#Install Docker
sudo apt install docker-ce

#Check Status
sudo systemctl status docker

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

#To apply the new group membership
su - ${USER}

#Confirm that your user is now added to the docker group
id -nG

#Add a user to the docker group
# sudo usermod -aG docker username

#Using the Docker Command
#docker [option] [command] [arguments]

#To view all available subcommands
docker

#To view the options available to a specific command
docker docker-subcommand --help

#To view system-wide information about Docker
docker info

#Search for images(ubuntu) available on Docker Hub
docker search ubuntu

#Download the official ubuntu image
docker pull ubuntu

#To see the images that have been downloaded
docker images

#Run a container using the latest image of Ubuntu. (-it switches gives interactive shell access into the container)
docker run -it ubuntu

#Update the package database inside the container
apt update

#Then install any application in it
apt install nodejs

#verify that Node.js is installed
node -v

#Any changes ymade inside the container only apply to that container
#To exit the container, 
exit

##Managing Docker Containers
#To view the active containers
docker ps

#To view all containers — active and inactive
docker ps -a

#To view the latest container
docker ps -l

#Start a specific container
docker start d9b100f2f636

#Stop a specific container
docker stop d9b100f2f636

#Remove a specific container
docker rm d9b100f2f636

#Commit the changes to a new Docker image instance
#docker commit -m "Commit Message" -a "Author Name" container_id repository/new_image_nam
docker commit -m "added Node.js" -a "sammy" d9b100f2f636 sammy/ubuntu-nodejs

#Lsting the Docker images again 
docker images

#Pushing Docker Images to a Docker Repository
#log into Docker Hub.
docker login -u docker-registry-username

#tag your image with your registry username.
docker tag sammy/ubuntu-nodejs docker-registry-username/ubuntu-nodejs

#push your own image using:
#docker push docker-registry-username/docker-image-name
docker push sammy/ubuntu-nodejs