How to add/remove PPAs?

Add:

sudo add-apt-repository ppa:ubuntu-sdk-team/ppa
sudo apt-get update

Remove-1:

sudo add-apt-repository --remove ppa:ubuntu-sdk-team/ppa
sudo apt-get update

Remove-2:

sudo add-apt-repository -r ppa:ubuntu-sdk-team/ppa
sudo apt-get update

Remove-3 using ppa-purge tool:

sudo apt-get install ppa-purge
sudo ppa-purge ppa:ubuntu-sdk-team/ppa

Remove-4:

ls -al /etc/apt/sources.list.d
sudo rm -i /etc/apt/sources.list.d/ubuntu-sdk-team-ppa-precise.list

[References]

• How can PPAs be removed?
• How to undo sudo add-apt-repository?
• How to upgrade QT Creator?