清单4没有定义一个命令类型。

Listing 4 does not define a single named type.

youdao

你可以创建自己所需要的新的对象或命令类型。

If you need a new type of object or command, you create one.

youdao

虽然前面两个命令类型不会对内核进行任何操作，但是其余命令则是用于读取日志消息或控制日志。

Although the first two command types perform no action within the kernel, the rest are used to read log messages or control aspects of logging.

youdao