1.1. help

$  etcdctl del --help
NAME:
        del - Removes the specified key or range of keys [key, range_end)

USAGE:
        etcdctl del [options] <key> [range_end] [flags]

OPTIONS:
      --from-key[=false]        delete keys that are greater than or equal to the given key using byte compare
  -h, --help[=false]            help for del
      --prefix[=false]          delete keys with matching prefix
      --prev-kv[=false]         return deleted key-value pairs