Backup of Repository Sources
Ubuntu maintains a list of repositories in the “/etc/apt/sources.list” file. Before doing anything or manually editing this text file, you should take a backup of sources by running the command below :
sudo cp /etc/apt/sources.list /etc/apt/sources.list.backup
Using PPA in Linux
Personal Package Archives (PPA) is a unique software repository intended for non-standard software/updates. The PPA allows application developers and Linux users to create their own repositories to distribute software. It allows us to upload Ubuntu source packages to be built and published as an apt repository by Launchpad. With PPA, we can easily get newer software versions or software that are not available via the official Ubuntu repositories.