You didn't specify exactly what type of matching you need, here's a very simple regex pattern match to return 1 if the line contains any one of three words. Otherwise, it returns 0.

 if ($line =~ /word1|word2|word3/) { return 1; }
 else { return 0; }
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Your code didn't show a call to a subroutine, so I'm assuming you *really* meant return. As duff said, this is what grep does.