#/!usr/bin/perl

use warnings;
use strict;

@ARGV or die "usage: $0 file\n";

my $file = shift @ARGV;

open my $fh, "<", $file or die "unable to open file";
binmode $fh;  # disable "\n" translation
my $data;
{
    local $/=undef;
    $data=<$fh>;
}
my $pattern=pack('CC', 0xff, 0xd9);
my $at=index($data, $pattern);

if ($at<0) {
    print "pattern not found\n"
}
else {
    print "pattern found at pos $at\n"
}