#! /usr/bin/perl -w
use strict;

package prime;
require Exporter;
our @ISA = qw(Exporter);
our @Export = qw(is_prime);
our $Version = 1.00;

sub is_prime {
        return 0 if int( $_[0] ) != $_[0];
        return 0 if $_[0] == 1;
        return 0 if $_[0] % 2 == 0 && $_[0] != 2;
   my $limit = int( sqrt( $_[0] ) ) + 1;
        for ( my $l = 3; $l <= $limit; $l += 2 ) {
                return 0 if $_[0] % $l == 0;
        }
        return 1;
}
1;

#! /usr/bin/perl -w
use strict;
use lib '/home/mm/perl/';
use prime;



foreach my $n ( 2..20 ) {
        print "$n ist eine Primzahl\n" if is_prime( $n );
}

package testdir::Lib;
require Exporter;
@ISA = qw(Exporter);
@EXPORT = qw(printv dateTime);
use strict;
[funktionen]
1;

testdir::Libs->func()

func()

Datei MyTest.pm:
--8<--
package MyTest;

use vars qw( $VERSION @ISA @EXPORT  @EXPORT_OK %EXPORT_TAGS );
use Exporter;
push @ISA, qw( Exporter );
@EXPORT = qw( foobar );

sub foobar {
        print "Hello World!\n";
}

1;

--8<--

Datei mytest.pl:
--8<--
#!/usr/bin/perl
use strict;
use warnings;
use MyTest;

foobar();

--8<--

package testdir::Lib;
require Exporter;
our @ISA = qw(Exporter);
our @EXPORTER = qw(printv);
use strict;

sub printv {
        my $key = shift;
        return $key;
}
1;

use warnings;
use strict;
use testdir::Lib;

printv("test");
testdir::Lib->printv("Test");