use File::Slurp;

my $file = read_file("file.bin");
my $data = unpack( 'H*', $file );

my $count =()= $data =~ /ff/g;
my $size = (stat("file.bin"))[7];

my $dec = $count/$size;
my $percentage = ($dec*100);

print "$count\n";
print "$size\n";
print $percentage;