使用xargs调用多个命令

冷不防 2022-11-26 15:58 70阅读 0赞

本文翻译自：[Calling multiple commands with xargs][]

cat a.txt | xargs -I % echo %

*In the example above, xargs takes `echo %` as the command argument.* **在上面的示例中，xargs将`echo %`作为命令参数。** *But in some cases, I need multiple commands to process the argument instead of one.* **但是在某些情况下，我需要多个命令而不是一个来处理参数。** *For example:* **例如：**

cat a.txt | xargs -I % {command1; command2; ... }

*But xargs doesn't accept this form.* **但是xargs不接受这种形式。** *One solution I know is that I can define a function to wrap the commands, but it's not a pipeline, I don't prefer it.* **我知道的一个解决方案是，我可以定义一个包装命令的函数，但这不是管道，我不喜欢它。** *Is there another solution?* **还有其他解决方案吗？**

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### \#1楼 ###

参考：[https://stackoom.com/question/tcgV/使用xargs调用多个命令][https_stackoom.com_question_tcgV_xargs]

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### \#2楼 ###

*One thing I do is to add to .bashrc/.profile this function:* **我要做的一件事是将.bashrc / .profile添加到此函数：**

function each() {
        while read line; do
            for f in "$@"; do
                $f $line
            done
        done
    }

*then you can do things like* **然后你可以做类似的事情**

... | each command1 command2 "command3 has spaces"

*which is less verbose than xargs or -exec.* **它不如xargs或-exec冗长。** *You could also modify the function to insert the value from the read at an arbitrary location in the commands to each, if you needed that behavior also.* **您也可以修改该函数，以将读取值插入命令中的任意位置（如果需要），从而将其插入每个命令。**

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### \#3楼 ###

*With GNU Parallel you can do:* **使用GNU Parallel，您可以：**

cat a.txt | parallel 'command1 {}; command2 {}; ...; '

*Watch the intro videos to learn more: [https://www.youtube.com/playlist?list=PL284C9FF2488BC6D1][https_www.youtube.com_playlist_list_PL284C9FF2488BC6D1]* **观看介绍性视频以了解更多信息： [https][https_www.youtube.com_playlist_list_PL284C9FF2488BC6D1] : [//www.youtube.com/playlist?list=PL284C9FF2488BC6D1][https_www.youtube.com_playlist_list_PL284C9FF2488BC6D1]**

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### \#4楼 ###

*Another possible solution that works for me is something like -* **对我有用的另一种可能的解决方案是-**

cat a.txt | xargs bash -c 'command1 $@; command2 $@' bash

*Note the 'bash' at the end - I assume it is passed as argv\[0\] to bash.* **注意最后的“ bash”-我假设它以argv \[0\]的形式传递给bash。** *Without it in this syntax the first parameter to each command is lost.* **如果没有使用此语法，则会丢失每个命令的第一个参数。** *It may be any word.* **可以是任何单词。**

*Example:* **例：**

cat a.txt | xargs -n 5 bash -c 'echo -n `date +%Y%m%d-%H%M%S:` ; echo " data: " $@; echo "data again: " $@' bash

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### \#5楼 ###

*You can use* **您可以使用**

cat file.txt | xargs -i  sh -c 'command {} | command2 {} && command3 {}'

*\{\} = variable for each line on the text file* **\{\} =文本文件中每一行的变量**

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### \#6楼 ###

*My current BKM for this is* **我目前的BKM是**

... | xargs -n1 -I % perl -e 'system("echo 1 %"); system("echo 2 %");'

*It is unfortunate that this uses perl, which is less likely to be installed than bash;* **不幸的是，它使用了perl，它比bash不太可能被安装。** *but it handles more input that the accepted answer.* **但它处理的输入要多于可接受的答案。** *(I welcome a ubiquitous version that does not rely on perl.)* **（我欢迎不依赖perl的无处不在的版本。）**

*@KeithThompson's suggestion of* **@KeithThompson的建议**

... | xargs -I % sh -c 'command1; command2; ...'

*is great - unless you have the shell comment character \# in your input, in which case part of the first command and all of the second command will be truncated.* **太好了-除非您在输入中输入了shell注释字符＃，否则第一个命令的一部分和第二个命令的所有部分都会被截断。**

*Hashes \# can be quite common, if the input is derived from a filesystem listing, such as ls or find, and your editor creates temporary files with \# in their name.* **如果输入源于文件系统列表（例如ls或find），并且您的编辑器创建名称为＃的临时文件，则哈希号＃很常见。**

*Example of the problem:* **问题示例：**

$ bash 1366 $>  /bin/ls | cat
    #Makefile#
    #README#
    Makefile
    README

*Oops, here is the problem:* **糟糕，这是问题所在：**

$ bash 1367 $>  ls | xargs -n1 -I % sh -i -c 'echo 1 %; echo 2 %'
    1
    1
    1
    1 Makefile
    2 Makefile
    1 README
    2 README

*Ahh, that's better:* **嗯，这样更好：**

$ bash 1368 $>  ls | xargs -n1 -I % perl -e 'system("echo 1 %"); system("echo 2 %");'
    1 #Makefile#
    2 #Makefile#
    1 #README#
    2 #README#
    1 Makefile
    2 Makefile
    1 README
    2 README
    $ bash 1369 $>

[Calling multiple commands with xargs]: https://oldbug.net/q/tcgV/Calling-multiple-commands-with-xargs
[https_stackoom.com_question_tcgV_xargs]: https://stackoom.com/question/tcgV/%E4%BD%BF%E7%94%A8xargs%E8%B0%83%E7%94%A8%E5%A4%9A%E4%B8%AA%E5%91%BD%E4%BB%A4
[https_www.youtube.com_playlist_list_PL284C9FF2488BC6D1]: https://www.youtube.com/playlist?list=PL284C9FF2488BC6D1