Somehow, the aliasing of the input to $_ is getting mixd up with the first element of @_

When you do screwed($_) variable $_ gets aliased to $_[0] inside screwed() as subroutine parameters always aliased to elements of @_ array inside the subroutine. So later when while loop modifies $_ it affects $_[0] too.

Shorter demo:

$_ = 1;

test($_);

sub test {
    $_ = 2;
    print $_[0], "\n";
}

# output of script
__END__
2
[download]

Yet another example why I think while(<>) { ... } considered harmful.

--
Ilya Martynov, ilya@iponweb.net
CTO IPonWEB (UK) Ltd
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