#!/usr/bin/perl

# This is a main program...

use strict;
use warnings;
use ZipUtilDemo; #unzipping imported by default here

print "starting main program\n";

unzipping(); #call unzipping sub in module ZipUtilDemo.pm

__END__

Prints:
starting main program
Sub unzipping called!

##</code><code>##

#!/usr/bin/perl
#This is file: ZipUtilDemo.pm
package ZipUtilDemo;

use strict;
use warnings;

use vars qw(@ISA @EXPORT @EXPORT_OK %EXPORT_TAGS $VERSION);
use Exporter;
our $VERSION=1.00;
our @ISA = qw(Exporter);
our @EXPORT    = qw( unzipping );
our @EXPORT_OK = qw( );

sub unzipping
{
   print "Sub unzipping called!\n"; #of course real code goes here.
}

1; #IMPORTANT return a true value!