参考：https://segmentfault.com/u/climatezhangxi 的https://segmentfault.com/q/1010000005040763
docker-machine restart&&eval "$(docker-machine env default)"&&docker-machine env 运行这么一串就好了
Docker初次安装运行出错：Cannot connect to the Docker daemon at ***/docker.sock. Is the docker daemon running?
原文：http://www.cnblogs.com/uinique/p/7795865.html