use strict;
use warnings;
use LWP::UserAgent;
use Data::Dumper;
my $url = "http://192.168.1.5/src/Login_validate.php";
my $mech = LWP::UserAgent->new();
my $response=$mech->post($url,[ 'name' => "username", 'passwd' => "password"]);
if(!$response->is_success())
{
    print "Failiure\n";
}
print Dumper \$mech->get("http://192.168.1.5/src/allbooks.php");

__DATA__
In allbooks.php I checked 
if(isset($_SESSION['id']) and if not I print "Session expired" error message.

So when I executed the above code, it prints "Session expired" message.

##</code><code>##

use strict;
use warnings;
use WWW::Mechanize;
use Data::Dumper;

my $url = "http://192.168.1.5/src/Login_validate.php";
my $mech = WWW::Mechanize->new();
my $response=$mech->post($url,[ 'name' => "username", 'passwd' => "passwd"]);
if(!$response->is_success())
{
   print "Failiure\n";
}
print Dumper \$mech->get("http://192.168.1.5/src/allbooks.php");

__END__
The above code print the html contents, echoed by allbooks.php and I'm not getting the session expired message.