--------------------------------------------
login.cgi:
--------------------------------------------

#!/usr/bin/perl -w

use strict; 
use warnings; 

use lib "/path/to/lib/";

use CGI; 
use CGI::Session;

# new query object
my $cgi = CGI->new;

# Get a new session
my $session = get_session($cgi);


print $session->header();
...
HTML template commands... 
...
print $template->output();

--------------------------------------------
form.cgi:
--------------------------------------------
#!/usr/bin/perl -w

use strict; 
use warnings; 

use lib "/path/to/lib/";

use CGI; 
use CGI::Session;

# new query object
my $cgi = CGI->new;

# Get a new session
my $session = get_session($cgi);

print $session->header();
...
HTML template commands... 
...
print $template->output();


---------------------------------------------------------
get_session.pm (to create or retrieve a session )
---------------------------------------------------------
sub get_session {
	
 my $cgi = shift;

 my ($session, $exist_sess_id);
  
 # Query the cookie and retrieve existing session id, if exists
 $exist_sess_id = $query->cookie( "CGISESSID" ) or undef;
	
 # Retrieve or Create a session
 $session = CGI::Session->new( undef, $exist_sess_id, 
					{ Directory => '/usr/sessions' })         
		or die "can't create session: $!";
								
 # Set expiration time
 $session->expire( "+10m" );
    
 return $session;
  
}


##</code><code>##

--------------------------------------------
login.cgi (modified)
--------------------------------------------

#!/usr/bin/perl -w

...
...

# new query object
my $cgi = CGI->new;

# Load and Delete existing session
delete_existing_session($cgi);

# Get a new session
my $session = get_session($cgi);

...
...


--------------------------------------------
delete_existing_session() 
--------------------------------------------

sub delete_existing_session {

 my $cgi = shift;

 my ($session, $exist_sess_id);

 # Query the cookie and retrieve existing session id, if exists
 $exist_sess_id = $cgi->cookie( "CGISESSID" ) or undef;

 # Load existing session 	
 $session = CGI::Session->load( $exist_sess_id );

 # Delete the session	
 $session->delete();
	
}