##### important lession here
#@dd = split(/\|/, $xx);
# @ddd = map {    $dd[$_] * 2 } 0..$#dd;



open(file,  '/myfile.dat' ); #### change to your file; 'myfile.dat'
  for (<file>) { $xxx .= unpack "b*", $_; }
#use bigint;
use PDL;
use PDL::NiceSlice;
$PDL::BIGPDL=1; ### needed for big files;


$xxx=~s/(.)/$zzz[$cx++]=$1;''/eg;

@yyy = reverse @zzz;

print @yyy,"\n";;
print @zzz,"\n";

$yyy=pdl(@yyy);
$zzz=pdl(@zzz);



$xxx=($yyy) ^ ($zzz);

for(0..$cx-1) {  $m5.=$xxx($_);  }

$m5=~s/\]|\[//g;

print $m5," looky ","\n";

#######################################################################################



   open(file1,  "+>", '/home/mark/Desktop/file3.dat');
   print file1  pack "b*",$m5;
   close file1;