#!/usr/bin/perl
use strict;
use warnings;
open(my $fh, '<', 'file.csv') or die $!;
{
    local $/ = \1;
    for (1 .. 10) {             # first 10 bytes of the file
        my $byte = <$fh>;
        print join("\t", ord($byte), $byte), "\n";
    }
}