It will not return an error to standard output if the file is not found. One way to test the return of the command is to use substitution, like shown in Listing 8.

即使找不到文件，它也不会向标准输出返回错误。

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Part of the problem is that the chip is just too intelligent - rather than a standard digital pulse it produces an analogue output that flummoxes the standard software used to test chips.

其中一个问题是芯片太“过于智能”了——与普通芯片的数字脉冲输出不同，它的输出是模拟信号，因此用于数字芯片的测试程序被它干扰了。

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