open IN,'<',$csvfile;
@data=<IN>;
close IN;
open OUT,'>',$newfile;
print OUT shift @data;
foreach my $line (@data) {$uniq{$line}=1;}
foreach my $line (keys %uniq) {print OUT $line;}
close OUT;

##</code><code>##

  DB<2> x \%data
0  HASH(0x555e18bb11b8)
   'A' => HASH(0x555e184f6448)
      'B' => HASH(0x555e18bb1218)
         'C' => ARRAY(0x555e18bb1290)
            0  0
            1  1
      'X' => ARRAY(0x555e18bb1278)
         0  5
  DB<3>