You are calling sort twice, which makes little sense. Also, your code does not even compile.

Most likely you wanted something like:

my @sorted = map {$_->[0]}
             sort { $a->[0] <=> $b->[0]
                    || $a->[1] <=> $b->[1]
                  }
             map {chomp;[$_,split(/\t/)]}
             <FILE>;
print OUT "$_\n" for @sorted;
[download]