Thank you dear monks! This was a good help!
My test script looks now like follows - and is working

#!/usr/bin/perl

use strict;
use warnings;

use Text::Autoformat;

$/ = '';

my $messy = <DATA>;

my $formatted = autoformat($messy, {all=>1});

print $formatted;

__DATA__

1. Analyze problem
3. Design algorithm
1. Code solution
5. Test
4. Ship
[download]

I would like nevertheless install a newer Perl with perlbrew

Could somebody help me with the linker problem? My Xcode is the newest version ...

marek