grep和perl regex之间的区别？ [英] Difference between grep and perl regex?

问题描述

我对grep的正则表达式和perl的正则表达式有所不同。考虑以下小测试：

I have a problem with what I think is a difference in grep's regex and perl's regex. Consider the following little test:

$ cat testfile.txt 
A line of text
SOME_RULE = $(BIN)
Another line of text

$ grep "SOME_RULE\s*=\s*\$(BIN)" testfile.txt 
SOME_RULE = $(BIN)

$ perl -p -e "s/SOME_RULE\s*=\s*\$(BIN)/Hello/g" testfile.txt
A line of text
SOME_RULE = $(BIN)
Another line of text

可以看到，使用正则表达式SOME_RULE \s * = \ s * \ $（BIN），grep可以找到匹配，但是perl无法使用相同的表达式来更新文件。我应该如何解决这个问题？

As you can see, using the regex "SOME_RULE\s*=\s*\$(BIN)", grep could find the match, but perl was unable to update the file using the same expression. How should I solve this problem?

感谢您的阅读并提前感谢您提供任何帮助，感谢！

Thanks for reading and thanks in advance for any help, appreciate it!

推荐答案

Perl希望'（'和'）'能够被转义。另外，shell在'$'上吃'\'，所以你需要：

Perl wants the '(' and ')' to be escaped. Also, the shell eats the '\' on the '$', so you need:

$ perl -p -e "s/SOME_RULE\s*=\s*\\$\(BIN\)/Hello/g" testfile.txt

（或者使用单引号 - 这在任何情况下都是非常明智的。）

(or use single quotes--which is highly advisable in any case.)

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