This is a GUI applications that is included in Ubuntu and allows you to change automatic updates settings, install drivers and manage PPAs and repositories. But if you have, open this file again with a text editor with root permissions (i.e.
If you want to start it from Terminal, the executable name is software-properties-gtk. gksu gedit /etc/apt/sources.list) and comment lines with '#' to disable them and/or delete lines to permanently remove them.
Or you plan to upgrade the OS to a newer version and the packages for this version weren't yet built in the PPA (to prevent errors in this situation, Ubuntu automatically disables third party PPAs when upgrading).
Or the PPA may not be maintained anymore and you get errors when updating apt cache.
When you're done, it will give you a Terminal command. You should now be able to update and install packages on your OS.There is no advantage to re-running the convenience script, and it can cause issues if it attempts to re-add repositories which have already been added to the host machine. This makes it easier for you to monitor and keep packages up-to-date.This post showed you three ways to remove unwanted PPAs from your apt configuration.A method for re-generating is also presented, in case you mess up.