gistfile1.txt

89
down vote
Go to https://repogen.simplylinux.ch.

Select your Country and Ubuntu Release.

For the default set of repositories, you need to enable these repositories.

All of the Ubuntu Branches repositories.
Security - Important Security Updates.
Security Sources Repository
Updates - Recommended Updates
Updates Sources Repository
If you want to install software from Canonical Partner Repositories (closed source software), enable the Ubuntu Partner Repositories (both of them).

Enable any 3rd party repository you wish to enable.

Now, click the Generate List button at the bottom of that page and you'll see your generated sources.list.

Replace the old sources.list with the new one
Run the following commands in a Terminal.

sudo mv /etc/apt/sources.list /etc/apt/sources.list.old
gksudo gedit /etc/apt/sources.list
Copy/paste all the text from the newly generated sources.list to this file. Save it and close Gedit.

Now, update apt.

sudo apt-get update
This will update your repository index with the current sources.list and then you can install any software using Software Center, Synaptic or apt-get.