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问题描述
我在这个 answer 上找到了在两个字符之间找到字符串的正则表达式.就我而言，我想找到 ‘ 和 ’ 之间的每个模式.这是正则表达式:
I have found on this answer the regex to find a string between two characters. In my case I want to find every pattern between ‘ and ’. Here's the regex :
(?<=‘)(.*?)(?=’)
确实，当我在 https://regex101.com/ 上尝试时，它确实有效.
Indeed, it works when I try it on https://regex101.com/.
问题是我想将它与 grep 一起使用，但它不起作用:
The thing is I want to use it with grep but it doesn't work :
grep -E '(?<=‘)(.*?)(?=’)' file
有什么遗漏吗?
推荐答案
那些是积极的前瞻和后视断言.您需要使用 PCRE(Perl Compatible Regex)启用它，也许最好使用 GNU grep 中的 -o 选项只获取匹配部分:
Those are positive look-ahead and look behind assertions. You need to enable it using PCRE(Perl Compatible Regex) and perhaps its better to get only matching part using -o option in GNU grep:
grep -oP '(?<=‘)(.*?)(?=’)' file
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