Follow the guides and install docker for your distro/OS.
Open a terminal and run the following docker command. You should get a similar output.
$ sudo docker --version
Docker version 19.03.5, build 633a0ea
Try to run the hello-world image:
$ sudo docker run hello-world
Unable to find image 'hello-world:latest' locally
latest: Pulling from library/hello-world
ca4f61b1923c: Pull complete
Digest: sha256:ca0eeb6fb05351dfc8759c20733c91def84cb8007aa89a5bf606bc8b315b9fc7
Status: Downloaded newer image for hello-world:latest
Hello from Docker!
This message shows that your installation appears to be working correctly.
...
Try to list the image:
sudo docker image ls
Try to list the container itself:
$ sudo docker ps --all
CONTAINER ID IMAGE COMMAND CREATED STATUS
54f4984ed6a8 hello-world "/hello" 20 seconds ago Exited (0) 19 seconds ago
As you noticed, the docker commands require you to be root. To not type sudo always, considering doing the following on Linux:
$ sudo groupadd docker
$ sudo usermod -aG docker $USER
You will need to relog your user or do the following:
$ newgrp docker
Be careful, as this gives the specified user root equivalent privileges!
Verify:
$ docker run hello-world