[r
  
oot@docker-test home]# docker ps -a
CONTAINER ID   IMAGE           COMMAND                  CREATED       STATUS       PORTS                                   NAMES
8634c76e01d1   nginx           "/docker-entrypoint.…"   2 hours ago   Up 2 hours   0.0.0.0:8080->80/tcp, :::8080->80/tcp   nginx

[root@docker-test home]# docker export 8634c76e01d1 > nginx.tar

[root@docker-test home]# cat nginx.tar | docker import - nginx:test
sha256:b47c6c6bddaf1433bba6ed64dc2daa4bafe569919556834c1a0b884bab228dc4
[root@docker-test home]# docker images
REPOSITORY   TAG       IMAGE ID       CREATED             SIZE
nginx        test      b47c6c6bddaf   5 seconds ago       140MB

[root@docker-test home]# docker run --name nginx-test -p 8081:80 -d nginx:test
docker: Error response from daemon: no command specified.
See 'docker run --help'.
##被docker export出来的镜像在启动的时候需要指定command，例如我启动上述nginx容器，需要指定Command

##Command可以通过下面命令查询到：
[root@docker-test home]# docker ps -a --no-trunc
CONTAINER ID                                                       IMAGE           COMMAND                                          CREATED       STATUS       PORTS                                   NAMES
8634c76e01d18cf913ebaee30a354b6c588b1780102de810c82c065501434b00   nginx           "/docker-entrypoint.sh nginx -g 'daemon off;'"   3 hours ago   Up 2 hours   0.0.0.0:8080->80/tcp, :::8080->80/tcp   nginx


[root@docker-test home]# docker run --name nginx-test -d -p 8081:80 nginx:test  /docker-entrypoint.sh nginx -g 'daemon off;'
d31501aa46ebc5c0fd9119a8895d537ef0c3d813d1e2783ca2b02642cdd86fb7

[root@docker-test home]# docker ps -a