#!/usr/bin/perl -w

use strict;

my $code = join '', <>;
$code =~ s/\s//gs;

open my $file, "<template.txt" or die;
my $template = join '', <$file>;
close $file;

my $i = 0;
foreach my $t (map {chr} unpack 'C*', $template)
{
   if( $t =~ /\s/s )
   {
      print $t;
   }
   else
   {
      $i < length($code) or die;
      print substr($code, $i, 1);
      $i++;
   }
}
$i == length($code) or die;