Listing 4 shows the beginning of the sample wrapper script, which defines a usage message that displays if you execute the script with no arguments or the wrong number of arguments.

清单4给出了此示例包装器脚本的开始部分，其中定义了一个使用消息，如果在没有参数或参数数量错误的情况下执行该脚本，就会显示这个消息。

youdao

Currently in Britain there is no legislation preventing under-18s from having plastic surgery and, as in Italy, there have been a number of horror stories of operations going wrong.

目前在英国，没有法律限制18岁以下女孩进行整形手术，但是在意大利，整容事故曾出不穷。

youdao

No, you've got the wrong number.

不，你的电话号码错了。

youdao

Using the wrong numbers is often worse than no number at all!

FORBES: The Value of Management Consulting: Proven