Docker 常用命令

[root@docker ~]# docker version
Client: Docker Engine - Community
 Version:           19.03.4
 API version:       1.40
 Go version:        go1.12.10
 Git commit:        9013bf583a
 Built:             Fri Oct 18 15:52:22 2019
 OS/Arch:           linux/amd64
 Experimental:      false
Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?