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

my $file        = "test.txt";
my $out1        = "chr1.gens";
my $out2        = "chr2.gens";
my $out3        = "chr3.gens";
open(IN,'<'.$file) || die "Can not open file $file: $!";
open OUT1, "> $out1" or die "Can't open $out1 : $!";
open OUT2, "> $out2" or die "Can't open $out2 : $!";
open OUT3, "> $out3" or die "Can't open $out3 : $!";

while(<IN>){
        
        if ($_ =~ m/^0/){       
        print  OUT1 "$_\n";     
        }       
        elsif ($_ =~ m/^1/){    
        print  OUT2 "$_\n";     
        }
        elsif ($_ =~ m/^2/){    
        print  OUT3 "$_\n";     
        }
        
}
close IN;
close OUT1;
close OUT2;
close OUT3;