File 1:           File 2:
0001,aname,bname  0001,aname,bname
0002,cname,bname  0003,aname,bname
0004,dname,bname  0005,fname,bname
0005,dname,bname
##</code><code>##

Final:
0001,aname,bname
0002,cname,bname
0004,dname,bname
##</code><code>##

use strict;
use warnings;
use CGI qw(:standard);
use CGI::Carp qw(warningsToBrowser fatalsToBrowser);

print "Cache-Control: max-age=30\n";

my %final;
my %compare1;
my %compare2;
my %compare3;
my $maxid = "2000";

open(DAT, "data/parsed-Black_Dragon.txt");
my @data = <DAT>;
close(DAT);
for(my $i = 0; $i < scalar(@data); $i++) {    # dump file data into hashed array
    my $id = substr($data[$i], 0, 4);    # get current planet id
    $compare1{$id} = $data[$i];
    delete $data[$i];
}
@data = ();

open(DAT, "data/parsed-BMoom.txt");
@data = <DAT>;
close(DAT);
for(my $i = 0; $i < scalar(@data); $i++) {    # dump file data into hashed array
    my $id = substr($data[$i], 0, 4);    # get current planet id
    $compare2{$id} = $data[$i];
    delete $data[$i];
}
@data = ();

open(DAT, "data/parsed-Litex.txt");
@data = <DAT>;
close(DAT);
for(my $i = 0; $i < scalar(@data); $i++) {    # dump file data into hashed array
    my $id = substr($data[$i], 0, 4);    # get current planet id
    $compare3{$id} = $data[$i];
    delete $data[$i];
}
@data = ();

open(DAT,">data/parsed-all.txt");    # open appropriate parsed file and clear it
close(DAT);
for(my $i = 1; $i <= $maxid; $i++) {
    my $currid = changeID($i);
	my $delid = changeID($i - 1);
	delete $compare1{$delid};
    delete $compare2{$delid};
    delete $compare3{$delid};
	next if( defined $compare1{$currid} && 
		defined $compare2{$currid} && 
		defined $compare3{$currid} && 
		$compare1{$currid} ne $compare2{$currid} && 
		$compare1{$currid} ne $compare3{$currid} && 
		$compare2{$currid} ne $compare3{$currid} );
    open(DAT,">>data/parsed-all.txt");
    if( defined $compare1{$currid} && !defined $compare2{$currid} && !defined $compare2{$currid} ) {
		print DAT $compare1{$currid};
		next;
	}
	if( defined $compare2{$currid} && !defined $compare1{$currid} && !defined $compare3{$currid} ) {
		print DAT $compare2{$currid};
		next;
	}
	if( defined $compare3{$currid} && !defined $compare1{$currid} && !defined $compare2{$currid} ) {
		print DAT $compare2{$currid};
		next;
	}
	if( defined $compare1{$currid} && defined $compare2{$currid} ) {
		if( $compare1{$currid} eq $compare2{$currid} ) {
			print DAT $compare1{$currid};
			next;
		}
	}
	if( defined $compare1{$currid} && defined $compare3{$currid} ) {
		if( $compare1{$currid} eq $compare3{$currid} ) {
			print DAT $compare1{$currid};
			next;
		}
	}
	if( defined $compare2{$currid} && defined $compare3{$currid} ) {
		if( $compare2{$currid} eq $compare3{$currid} ) {
			print DAT $compare2{$currid};
			next;
		}
	}
    close(DAT);
}
print "Location: planetDiscovered.cgi\n\n";
exit;

sub changeID {
	return sprintf "%04d", $_[0];
}
##</code><code>##

0001,Nunki 2 1,5847,71%,0.71,4151.37,ThrevenGuard,-18,-26