Egrep / Sed：只返回正则表达式匹配，而不是整行 [英] Egrep/Sed: return only the regex match, not the whole line

问题描述

我有一个多行文档，我希望在其中提取特定的关键字和单词。它看起来像这样：

 这是关键词1行1. 
 
这是行2. 
 
这是关键的第二行3. 
  

如果我使用<$ c $

 这是关键word1 line 1. 
 
这是关键的word2行2. 
  

然而，我'd喜欢将输出作为匹配，而不是整行，即：

$ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $>
关键字2

有没有办法做到这一点？这似乎是一个足够简单的任务，但我一直在头撞墙。感谢您的帮助！

解决方案

grep（1） 有一个 -o 标志只输出该行的匹配部分。从手册页：

  -o， - 仅匹配
仅显示匹配PATTERN的匹配行的部分。 
  

你的模式不适合获得你想要的输出，虽然。尝试：

$ $ p $ lt; code> $ egrep -o'key \w +'文件
关键字1
关键字2

I have a multiline document from which I'm looking to extract a particular keyword and the word after that. It looks like this:

This is key word1 line 1.

This is line 2.

This is key word2 line 3. 

If I use egrep 'key [^s]+ ', the output is:

This is key word1 line 1.

This is key word2 line 2. 

However I'd like the output to be the match only as opposed to the whole line, that is:

key word1

key word2

Is there a way to do that? It seems a simple enough task but I've been banging my head against the wall at this. Thanks for your help!

解决方案

grep(1) has a -o flag that outputs only the matching part of the line. From the man page:

  -o, --only-matching
      Show only the part of a matching line that matches PATTERN.

Your pattern isn't right to get the output you want, though. Try:

$ egrep -o 'key \w+' file 
key word1
key word2

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