#!/bin/perl -w 
use strict; 
#variables you can change to suit your needs 
my $column_separator = ","; 
my $column_number = "2";
$column_number--; 
my @lines=<DATA>; 
foreach my $line (@lines){ 
		chomp($line);
		my @columns = split(/$column_separator/,"$line"); 
		print $columns[$column_number],"\n"; 
}

__DATA__
1,2,3,4
A,B,C,D