$ cat pivot.pl
#!/pro/bin/perl

use strict;
use warnings;

use Text::CSV_XS;
use Spreadsheet::Read;

my $ss  = ReadData (shift)->[1];
my $csv = Text::CSV_XS->new ({ binary => 1, auto_diag => 1, eol => "\r\n" });

$csv->print (*STDOUT, [@{$ss->{cell}[$_]}[1..$ss->{maxrow}]]) for 1 .. $ss->{maxcol};
$ cat test.csv
a,b,c,d,e,f
1,2,3,4,5,6
2,3,4,5,6,7
3,4,5,6,7,8
4,5,6,7,8,9
$ perl pivot.pl test.csv
a,1,2,3,4
b,2,3,4,5
c,3,4,5,6
d,4,5,6,7
e,5,6,7,8
f,6,7,8,9
$