To install Cinnamon 2.6 on Ubuntu 15.04 and Ubuntu 14.04, open Terminal and run the following command:
sudo add-apt-repository ppa:gwendal-lebihan-dev/cinnamon-nightly
sudo apt-get update
sudo apt-get install cinnamon
Uninstall and remove the Cinnamon 2.6 Desktop Environment:
sudo apt-get install ppa-purge
sudo ppa-purge ppa:gwendal-lebihan-dev/cinnamon-nightly
