BTW:
sudo apt-add-repository --remove ppa:graphics-drivers/ppa
can (and should) be used instead of:
sudo rm /etc/apt/sources.list.d/graphics-drivers-ubuntu-ppa-xenial.list
(I just didn't know that apt-add-repository has --remove option.)
And the recipe in #68-#69 in only for Ubuntu 16.04.1.
BTW: drivers/ ppa sources. list.d/ graphics- drivers- ubuntu- ppa-xenial. list
sudo apt-add-repository --remove ppa:graphics-
can (and should) be used instead of:
sudo rm /etc/apt/
(I just didn't know that apt-add-repository has --remove option.)
And the recipe in #68-#69 in only for Ubuntu 16.04.1.