安装方法

    1. curl -L https://github.com/docker/machine/releases/download/v0.16.2/docker-machine-`uname -s`-`uname -m` >/tmp/docker-machine &&
    2.     chmod +x /tmp/docker-machine &&
    3.     sudo cp /tmp/docker-machine /usr/local/bin/docker-machine

    查看版本号：https://github.com/docker/machine/releases