centos7/BCOS-Docker使用问题

[kuangfengxing1hao]

我想要查看工作状态
执行"# 连接到容器"这一步，
输入命令:
$ docker exec -it $(docker ps -a | grep bcos-node-0 | awk 'NR==1{print $1}') sh
结果是这样:
"docker exec" requires at least 2 arguments.
See 'docker exec --help'.
Usage: docker exec [OPTIONS] CONTAINER COMMAND [ARG...]
Run a command in a running container
请问是命令出错了吗，请大神帮解决一下