help - Meta-Command Help 可以列出所有元命令和每个命令的简单说明的
Again, we simply add a meta-programming command to indicate that a catch belongs to a boat.
同样只需添加元编程命令以表示一个捕获物属于一艘船。
But if you must use the shell and you can't limit the data that comes in, you need to escape every potential meta-character before sending it in a command to the shell.
但是如果您必须使用shell并且不能限制到达的数据，那么就需要在将命令中的字符发送到shell中之前对可能存在的每个元字符进行转义。
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