Install Plasma 5 KDE ubuntu - Cannot add PPA

I am trying to install Plasma 5 KDE on my ubuntu 14.04 with the following commands:

sudo apt-add-repository ppa:kubuntu-ppa/next-backports
sudo apt-get update
sudo apt-get dist-upgrade
sudo apt-get install kubuntu-plasma5-desktop plasma-workspace-wallpapers

It fails after the first command with the message:

 Cannot add PPA: 'ppa:kubuntu-ppa/next-backports'.
Please check that the PPA name or format is correct.

I got all from the following link

What is this error-message and how do I solve it?

2 Answers

ppa:kubuntu-ppa/next-backports is a valid name for a PPA, but there is no PPA with this name. Here is a list of valid PPAs of the “Kubuntu Package Archives” team.

• backports – Kubuntu Backports
• beta – Kubuntu Beta Backports
• experimental – Kubuntu Experimental
• ppa – Kubuntu Updates
• staging-frameworks – Kubuntu Staging Frameworks
• staging-kdeapplications – Kubuntu Staging KDE Applications
• staging-misc – Kubuntu Staging Misc
• staging-plasma – Kubuntu Staging Plasma

Therefore install an existing PPA, e.g.

sudo apt-add-repository ppa:kubuntu-ppa/backports

Case 1: You are not using any proxy servers

• Re-install the certificates,Use::-

  sudo -E add-apt-repository ppa:ppaname/ppa

  Example --- sudo -E add-apt-repository -y ppa:videolan/stable-daily

  [sudo -E preserves the user environment, including any proxy config ]

Case 2: If you are using any proxy servers

1. Configure The Proxies in the Terminal

    If there is no username and password for the proxy settings ::- export http_proxy= export https_proxy= In case of Username and Password for the proxy settings use this ::- export http_proxy= export https_proxy= After this do::- sudo -E add-apt-repository ppa:ppaname/ppa

   Example --- sudo -E add-apt-repository -y ppa:videolan/stable-daily

   [sudo -E preserves the user environment, including any proxy config ]