1.自动下载并且创建容器
Now verify that the installation has worked by downloading the ubuntu image and launching a container.
sudo docker run -i -t ubuntu /bin/bash
参考地址：http://docker-doc.readthedocs.org/zh_CN/latest/installation/ubuntulinux.html
原文：http://www.cnblogs.com/davygeek/p/4562877.html