I installed docker on a Debian 7 machine in the following way
$ echo deb http://get.docker.io/ubuntu docker main > /etc/apt/sources.list.d/docker.list
$
If it's just a test installation of Docker (ie not production) and you don't care about doing a nuclear clean, you can:
clean all containers:
docker ps -a | sed '1 d' | awk '{print $1}' | xargs -L1 docker rm
clean all images:
docker images -a | sed '1 d' | awk '{print $3}' | xargs -L1 docker rmi -f
Again, I use this in my ec2 instances when developing Docker, not in any serious QA or Production path. The great thing is that if you have your Dockerfile(s), it's easy to rebuild and or docker pull
.