my $buffer;

open INFILE, "test.text" or die "Can't open test.txt for reading: $!\n";
open OUTFILE, ">test_updated.bin" or die "Can't open test_updated.bin for writing: $!\n";
binmode OUTFILE;

my $line = <INFILE>;
chomp $line;
my @list = split //, $line;
my $hex_value;
my $i =1;
foreach my $character (@list)
{
  if($i%2 == 0)
  {
    $hex_value .= $character;
    syswrite OUTFILE, hex($hex_value);
  }
  elsif($i%2 == 1)
  {
    $hex_value = "0x".$character;
  }
  $i++;
}