How to Add a Repository to an Ubuntu Instance

To add a repository to a linux cloud instance running Ubuntu, add the details for the repository you wish to add to /etc/apt/sources.list or to the /etc/apt/sources.list.d directory. See this example from /etc/apt/sources.list:

deb http://ch.archive.ubuntu.com/ubuntu/ saucy main restricted

To update the local package index so it includes the new repository, run the following command:

(ubuntu) $ sudo apt update

You can now run apt commands to install or update packages from the repository.