Named Pipe File System 命名管道文件系统
This can be restated as follows: the program should operate the same, irrespective of its source of input (a file, a pipe, or the terminal) and of its output destination.
该特性可以重新叙述如下：不管程序的输入源(文件、管道或终端)和输出目的地是什么，程序都应该以同样的方式工作。
If the output stream was stdout, and if it was not redirected to a file or a pipe, the selected pages will appear on the screen.
如果输出流是标准输出，并且没有被重定向至文件或管道，则选定的页将出现在屏幕上。
Be sure to pipe the output to a file for further study.
应确保将输出通过管道发送到一个文件中，以便于进一步的研究。
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