Actually, nevermind about the blank line in the result set. I see that yours has it also. Must come from the "+1" in the print.

Erm, no. The header line, and the following blank line in the output, are printed by this line:

print scalar <DATA>;
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It has one newline because I didn't chomp it. And the second, because I have -l on the hashbang line:

#! perl -slw
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Which has the affect of automatically adding "\n" to the end of every print line.

The +1 in this line:

    print join "\t", $label, map $_+1, sort{
        $order[ $a ] <=> $order[ $b ]
    } 0 .. $#order;
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converts the numbers 0 .. 3 used to index the array while sorting. into the numbers 1 .. 4 used for your desired output.