1.1. help

$  etcdctl member add --help
NAME:
        member add - Adds a member into the cluster

USAGE:
        etcdctl member add <memberName> [options] [flags]

OPTIONS:
  -h, --help[=false]    help for add
      --learner[=false] indicates if the new member is raft learner
      --peer-urls=""    comma separated peer URLs for the new member.