Updating repositories in ubuntu
They have been ignored, or old ones used instead This will remove all the cached packages and force the system to re-download them again.
To get started with Docker Engine - Community on Ubuntu, make sure you meet the prerequisites, then install Docker.
To install Docker Enterprise Edition (Docker EE), go to Get Docker EE for Ubuntu instead of this topic.
To learn more about Docker EE, see Docker Enterprise Edition.
It exists some methods to install or remove PPA on Ubuntu systems.
command which adds a PPA repository to your package manager's configuration.
For all its benefits, occasionally Ubuntu can throw some errors when updating the system that can confuse and even worry a new user.