UNIX下管道的疑问
在 K & 的 Unix 编程环境中P，上面写着
" 管道中的程序实际上是同时运行的，而不是一个接一个地运行。
这意味着管道中的程序可以是交互式的；”
程序如何同时运行？
例如：$ who | grep 玛丽 |厕所-l
grep mary 将如何执行直到 who 运行或 wc -l 将如何执行直到 it 知道以前程序的结果吗？
In The Unix Programming Environment by K & P, it is written that
" The programs in a pipeline actually run at the same time, not one after another.
This means that programs in a pipeline can be interactive;"
How can programs run at same time?
For ex: $ who | grep mary | wc -l
How grep mary will be executed until who is run or how wc -l will be executed until it
knows results of previous programs?
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who将输出一行数据，grep将接收该stdout< /code>，然后wc将读取并计数who可能还为grep等每个程序 写出更多数据需要前一个的结果，但在它可以开始工作之前不需要所有结果，这就是为什么流水线是可行的。
whowill output a line of data, whichgrepwill then receivestdout, whichwcwill then read and countwhomay also have been writing out more data forgrepetcEach program needs the results of the previous one, but it doesn't need all of the results before it can start working, which is why pipelining is feasible.