#!/usr/bin/perl
use strict;
use warnings;

# 1 -> Zeile 1
# 2 -> Zeile 2
# ...
my $position=100; # -> Zeile 100
my $file='test.dat';

my $bytepos=($position-1)*2; # *3 wenn \r\n

open(my $fh, '<', $file) or die("ERROR open $file ($!)\n");
my $data='';
read($fh,$data,1,$bytepos);
close($fh);

print "$data\n";