如何将通信输出通过管道传输到文件? [英] How do I pipe comm outputs to a file?

问题描述

我使用了 comm 命令来比较两个文件，但我无法将它传送到第三个文件:

I've used the comm command to compare two files, but I'm unable to pipe it to a third file:

comm file1 file2 > file3 

comm: file 1 is not in sorted order
comm: file 2 is not in sorted order

我该怎么做?文件已经排序.

(comm file1 file2 工作并打印出来)

(comm file1 file2 works and prints it out)

样本输入:
文件 1:

sample input:
file1:

21
24
31
36
40
87
105
134
...

文件 2:

10
21
31
36
40
40
87
103
...

comm file1 file2:有效

comm file1 file2: works

comm file1 file2 > file3 

comm: file 1 is not in sorted order
comm: file 2 is not in sorted order

推荐答案

您已按数字排序；comm 适用于词法排序的文件.

You've sorted numerically; comm works on lexically sorted files.

例如，在 file2 中，第 103 行与第 21..87 行明显乱序.您的文件必须是plain sort 排序".

For instance, in file2, the line 103 is dramatically out of order with the lines 21..87. Your files must be 'plain sort sorted'.

如果你有 bash (4.x)，你可以使用进程替换:

If you've got bash (4.x), you can use process substitution:

comm <(sort file1) <(sort file2)

这会运行这两个命令并确保 comm 进程能够像读取文件一样读取它们的标准输出.

This runs the two commands and ensures that the comm process gets to read their standard output as if they were files.

失败:

(
sort -o file1 file1 &
sort -o file2 file2 &
wait
comm file1 file2
)

这使用并行性来同时对文件进行排序.子外壳(在 ( ... ) 中)确保您最终不会等待其他后台进程完成.

This uses parallelism to get the file sorted at the same time. The sub-shell (in ( ... )) ensures that you don't end up waiting for other background processes to finish.

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