$ ./1.bliako.pl 
./1.bliako.pl : ngram-length must be a positive integer.
$ cat 1.bliako.pl 
#!/usr/bin/env perl

# FILE: analyse_DNA_sequence.pl
# by bliako

use strict;
use warnings;

use Getopt::Long;
use Data::Dump qw/dump/;
use lib '.';

use Markov::Ndimensional;