#!/usr/bin/perl
use strict;
use IO::All;
use warnings;
use Data::Dumper;

my $output = io('out.txt');
my @lines = io('in.txt')->chomp->slurp;

my %hash;
while (defined(my $str = shift @lines)) {
    if (index($str, 'XX') != -1) {
	my @array = split /=/, $str;
	$array[1] =~ s/^\s+|\s+$//g;
	$hash{$array[1]} = $array[0];
    }
}

my @final = keys %hash;
print Dumper \@final;

while (defined(my $strOut = shift @final)) {
    $output->write ($strOut . "\n");
}

__END__

$ perl test.pl
$VAR1 = [
          'XX00011',
          'XX111X1',
          'XX0001X',
          'XX0010X',
          'XX00X1X',
          'XX0011X',
          'XXXX0XX',
          'XX01X10',
          'XXX1XX0',
          'XX010X1',
          'XX11XX0',
          'XX110X1',
          'XX0X0X1',
          'XXXX1XX',
          'XX0X10X',
          'XX1XXXX',
          'XX1X0X1',
          'XX00X11',
          'XX0XX1X',
          'XX110X0',
          'XXX0XX0',
          'XX11XXX',
          'XX10XX0'
        ];
$ cat out.txt
XX00011
XX111X1
XX0001X
XX0010X
XX00X1X
XX0011X
XXXX0XX
XX01X10
XXX1XX0
XX010X1
XX11XX0
XX110X1
XX0X0X1
XXXX1XX
XX0X10X
XX1XXXX
XX1X0X1
XX00X11
XX0XX1X
XX110X0
XXX0XX0
XX11XXX
XX10XX0