Because cut and paste is for monkeys.

Simian (Similarity Analyser) identifies duplication in Java, C#, C, C++, COBOL, Ruby, JSP, ASP, HTML, XML, Visual Basic source code and even plain text files. In fact, simian can be used on any human readable files such as ini files, deployment descriptors, you name it.

It will handle Python in the near future, they say. They say nothing about handling Perl. That reminds me of something I read recently: "the higher the likelyhood of a random string being a valid program, the less help you can get from tools".

In the tools vs. language argument, I'm definitely in the language camp. But I'm also not one to turn down good help.