That also removes cat.msg, vain.msg, etc. Closer to the original intent (as best as I can tell) would be: 

$line =~ s[v?(a?(c?(a?(t?(i?(o?(n?(\.?(m?(­s?g))))))))))][];

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                - tye

In reply to Re^2: more efficient regular expression please (parens) by tye
in thread more efficient regular expression please by Anonymous Monk

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