#!/usr/bin/perl
use strict;
use warnings;

my $cnt;

while(<DATA>) {
    $cnt++;
    print "$cnt line\n";
    s/(\d),(?=\d)/$1|$2/g;
    print;
}

__DATA__
work with 19,43  or so
14,99
we have, at most, 14,23 to do though some say it is 18,44
Without digits, all the , will remain.
With digits 9, Ah ha! or
With,3 no change for a 2nd line
But again 3,4,5,6 all have bars.