#!/usr/bin/perl -w
use strict;

die "Usage: ", $0 =~ /([^\/]+)$/, " <file>\n" unless @ARGV;
open my $fh, $ARGV[0] or die "$ARGV[0]: $!\n";
binmode $fh;

my ($hex, $char, $count);
{
    my $res = sysread $fh, my $s, 1;
    if ($res){
        $hex .= sprintf("%02X ", ord($s));
        $char .= $s =~ /[[:print:]]/ ? $s : '.';
    }
    if ((++$count % 20 == 0) || !$res){
        printf "%-60s%4s%-20s\n", $hex, ' ', $char;
        $hex = $char = undef;
    }
    redo if $res;
}
close $fh;