Also when trying to access it from Ubuntu software center the entry that says "Edit software sources" is greyed out. Finally when running
cp /usr/share/applications/software-properties-gtk.desktop ~/.local/share/applications/
I receive the following message
cp: cannot stat `/usr/share/applications/software-properties-gtk.desktop': No such file or directory
And when I run
gedit ~/.local/share/applications/software-properties-gtk.desktop
It opens a blank text file in geddit.
How can I get a software sources back?