使用grep进行就地处理 [英] In-place processing with grep

问题描述

我有一个调用grep来处理文本文件的脚本。目前我正在做这样的事情。

  $ grep'SomeRegEx'myfile.txt> myfile.txt.temp 
 $ mv myfile.txt.temp myfile.txt 
  

I' m想知道是否有任何方法可以进行就地处理，如将结果存储到相同的原始文件而不必创建临时文件，然后在处理完成后用temp文件替换原始文件。

当然，我欢迎评论为什么应该这样做，但我主要关心它是否可以完成。在这个例子中，我使用 grep ，但是我对Unix工具一般很感兴趣。谢谢！

解决方案

Perl有 -i 开关， code> sed 和 Ruby

  sed -i.bak -n'/ SomeRegex / p'文件
 
 ruby​​ -i.bak -ne'打印if / SomeRegex /'文件
  

但是请注意，它所做的只是在后端创建临时文件，而您认为这些文件您没有看到，就这些了。除了 grep

awk

  awk'/ someRegex /'文件> t&& mv t file 
  

bash

  while read -r line; do * someregex *中的情况$ lineecho$ line;; esac; done< file> t&& mv t file 
  

I've got a script that calls grep to process a text file. Currently I am doing something like this.

$ grep 'SomeRegEx' myfile.txt > myfile.txt.temp
$ mv myfile.txt.temp myfile.txt

I'm wondering if there is any way to do in-place processing, as in store the results to the same original file without having to create a temporary file and then replace the original with the temp file when processing is done.

Of course I welcome comments as to why this should or should not be done, but I'm mainly interested in whether it can be done. In this example I'm using grep, but I'm interested about Unix tools in general. Thanks!

解决方案

Perl has the -i switch, so does sed and Ruby

sed -i.bak -n '/SomeRegex/p' file

ruby -i.bak -ne 'print if /SomeRegex/' file

But note that all it ever does is creating "temp" files at the back end which you think you don't see, that's all.

Other ways, besides grep

awk

awk '/someRegex/' file > t && mv t file

bash

while read -r line;do case "$line" in *someregex*) echo "$line";;esac;done <file > t && mv t file

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