#!/usr/bin/perl
use strict;
use warnings;
use Text::Wrap;

my $s = '1234,4325,545678910,6544,4345,5443,3455,4321';

$Text::Wrap::columns = 15;
$Text::Wrap::break = ',';

# use this line if you need trailing commas at the end of each line
#$Text::Wrap::separator = ",\n";

print wrap('', '', $s);

__END__
C:\Old_Data\perlp>perl text_wrap2.pl
1234,4325
545678910,6544
4345,5443,3455
4321