I have noticed that Kubuntu (I am using 12.04 version) doesn't use exactly the same repositories that Ubuntu. Or at least, that is what I think.
For example, if I search for Steam on Muon Software Center or Muon Package Manager, I just can't find it; even if I use sudo apt-get install steam-launcher. But on Ubuntu I have no problem. Why?
That's why I think Ubuntu has some repositories that Kubuntu doesn't. In this case (I don't know if I'm right), how can I add this Ubuntu repositories?
Steam is only an example. There are many packages that I can't find on Kubuntu. Another example: Motorbike (a game) (https://apps.ubuntu.com/cat/applications/precise/motorbike/). sudo apt-get install motorbike doesn't work.
Regards.
Best Answer
Kubuntu Wikipedia page: Every package in Kubuntu shares the same repositories as Ubuntu. However Steam and Motorbike aren't in the default ubuntu/kubuntu repositories. So you will have to enable the universe and multiverse repositories.
Managing Repositories in Kubuntu
Kubuntu uses KPackageKit for software management. To open it, click on your Kmenu, then open System Settings.
Next, select "Add and Remove Software"
Click the "Settings" button, then select "Edit Software Sources".
You will be prompted for your password in order to proceed
Next, go the the "Updates" tab. From here, you can enable/disable some of the official Ubuntu repositories and change your update settings. You should enable the universe and the multiverse repos.
Or, you could just type a line or two of commands and get the job done as follows:
then
then
Kubuntu repository installation instruction page