I always forget about the POSIX stuff, of course I also wish Perl had a matrix operator so that I could say something like:

printf '%d,%02d,%02d', (1900,1,0) plus reverse +(localtime)[3..5];
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Er... I guess really that's just a vector operator... I know there are modules to do that, but I think it should be part of the Perl core... otherwise what's the point? I could just as easily write it:

sub add_vectors
{
    my @left = @{ shift };
    my @right = @{ shift };
    my @result = ();
    my $index = $#left > $#right ? @left : @right;
    while( --$index >= $[ )
    {
        $left[$index]   = 0 if not defined $left[$index];
        $right[$index]  = 0 if not defined $right[$index];
        $result[$index] = $left[$index] + $right[$index];
    }
    return \@result;
}
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A sloppy first pass, but you get the idea.