The Software Center in Ubuntu doesn’t contain all software. To install third-party software, you will have to add Personal Package Archives (PPA) to the system. Although it’s easy to add and remove PPAs to Ubuntu through the terminal, some people consider anything involving typing commands to be “hard to use.” If you find yourself in this camp, don’t worry. You can add, manage, and remove PPAs through Ubuntu’s Software & Updates. Let’s see how that works.
Click on Ubuntu’s main menu icon or press the menu (“windows”) key on your keyboard. Type “software” in the search field.
Choose “Software & Updates” from the available entries.
Software & Updates includes the default package (“software”) sources for Ubuntu, by its creators, Canonical. To add a new repository (“source for packages/non-Canonical software”), move to the “Other Software” tab.
When there, click on the “Add” button on the bottom left of the window.
Enter the PPA you want to add for your new software source in the window that pops up.
Sublime Text’s repository was used for this example, so in this case, the “APT line” is:
After clicking “Add Source,” the new repository appeared after the existing “Canonical Partners.”
That wasn’t enough to be able to install Sublime Text, though. To be sure of the software’s authenticity and the trustworthiness of the repository, we also have to add a PGP key.
In the terminal, adding a new PPA key is just a command away. When working The GUI way, the process is more complicated. First, visit the provided key’s URL with your favorite browser.
The browser will prompt you to either open or save the key’s file. Choose how you’d like to save it.
Return to “Software & Updates” and move to the “Authentication” tab.
Click on the “Import Key File …” on the bottom left of the window.
Choose the key file you downloaded and saved to import the authentication key.
That’s it. You just added a new repository to Ubuntu. After your next software update, the software available from this source will appear among Canonical’s “official” suggestions, and you can install it as usual.
If sometime in the future you decide to stop using the software and wish to remove it, uninstall it like you would any other piece of software. Then, return to “Software & Updates.” Like before, move to the “Other Software” tab but this time select its repository and click on “Remove.”
Proceed by also removing the Authentication Key for it and then updating your software sources one more time.