Linux的我为什么不能管找到结果RM？ [英] Linux why can't I pipe find result to rm?

问题描述

对不起，如果这是一个noobie问题，但我不能找到一个很好的答案。

sorry if this is a noobie question but I can't find a good answer.

要找到然后取出东西，我可以使用

To find then remove something I can use

find . -name ".txt" -exec rm "{}" \;

但为什么我就不能管的结果，RM像

But why can't I just pipe the results to rm like

find . -name ".txt" | rm 

就像我觉得应该是到grep

like I would pipe it to grep

find . -name ".txt" | grep a

我从某处，RM阅读并不需要从标准输入，因此，我不能管，但到底是什么意思呢？当我在RM型A.TXT它从标准输入读取就像我可以grep吧？或者是有标准输入和命令行之间的差异。救命啊！

I've read from somewhere that rm doesn't take input from stdin and therefore I can't pipe it but what does that mean? When I type in rm a.txt it reads from standard input just like I can grep right? Or is there a difference between stdin and command line. Help!

推荐答案

要扩大@Alex Gitelman的回答：是的，有标准输入和命令​​行之间的差异

To expand on @Alex Gitelman's answer: yes, there's a difference between "standard input" and the command line.

当你键入 RM A.TXT b.txt c.txt ，你以后 RM 列出文件被称为的参数的，并提供通过一个特殊的变量RM（名为的argv 内部）。标准输入，而另一方面，看上去到Unix程序就像一个名为标准输入文件。程序可以从该文件中读取数据，就像它，如果它打开磁盘上的常规文件，并且从读取。

When you type rm a.txt b.txt c.txt, the files you list after rm are known as arguments and are made available to rm through a special variable (called argv internally). The standard input, on the other hand, looks to a Unix program like a file named stdin. A program can read data from this "file" just as it would if it opened a regular file on disk and read from that.

RM ，像许多其他程序，需要在命令行及其参数，但忽略标准输入。你可以管任何事情它你喜欢的;它会只是把这些数据了。这就是的xargs 就派上用场了。它读取标准输入线，把他们变成命令行参数，这样可以有效地管数据到另一个程序的命令行。这是一个巧妙的方法。

rm, like many other programs, takes its arguments from the command line but ignores standard input. You can pipe anything to it you like; it'll just throw that data away. That's where xargs comes in handy. It reads lines on standard input and turns them into command-line arguments, so you can effectively pipe data to the command line of another program. It's a neat trick.

例如：

find . -name ".txt" | xargs rm
find . -name ".txt" | grep "foo" | xargs rm  

请注意，这将无法正常工作，如果有包含换行符或空格的任何文件名。
为了处理包含换行符或空格，你应该使用的文件名：

Note that this will work incorrectly if there are any filenames containing newlines or spaces. To deal with filenames containing newlines or spaces you should use instead:

find . -name ".txt" -print0 | xargs -0 rm

这将告诉找到以空字符，而不是一个新行终止的结果。
然而，的grep 不会像以前那样工作，然后。相反，使用：

This will tell find to terminate the results with a null character instead of a newline. However, grep won't work as before then. Instead use this:

find . -name ".txt" | grep "foo" | tr "\n" "\0" | xargs -0 rm

这个时间 TR 用于所有的换行转换成空字符。

This time tr is used to convert all newlines into null characters.

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