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

use vars '$var';

package main;

my $var = "Welt";
print "Namensraum: main\n";
print "Hallo " . $var . "\n";

package foo;
print "Namesraum: foo\n";
print "Hallo " . $var . "\n";

$var = "du";

print "Hallo " . $var . "\n";