# usermod -e 2010-12-31 nama_user

kemudian cek hasil nya :
# chage -l nama_user
Last password change : Oct 05, 2010
Password expires : never
Password inactive : never
Account expires : Dec 31, 2010
Minimum number of days between password change : 0
Maximum number of days between password change : 99999
Number of days of warning before password expires : 7

reference :
1. http://techgurulive.com/2008/09/15/how-to-show-expiration-date-of-linux-user-account/
2. http://linux.die.net/man/8/usermod
3. http://www.linuxforums.org/forum/red-hat-fedora-linux/93498-how-reactivate-expired-account-linux-root-user.html
4. http://www.comptechdoc.org/os/linux/commands/linux_cruserman.html

1. Daftar dulu disini http://recaptcha.net/
2. Download librarry nya disini : http://code.google.com/p/recaptcha/downloads/list?q=label:phplib-Latest
3. Rename file recaptchalib.php jadi recaptcha_helper.php , truss… taruh di folder helpers (/system/application/helpers)
4. Tambahkan function berikut di file recaptcha_helper.php : function recaptcha()
{
$CI =& get_instance();
$CI->config->load('recaptcha');
$public_key = $CI->config->item('recaptcha_public_key');
$message = isset($CI->validation->recaptcha_error)
? $CI->validation->recaptcha_error : '';
return recaptcha_get_html($public_key, $message);
}

5. Buat sebuah class bernama MY_Validation dan taruh di folder librarries, kemudian tambahkan function sebagai berikut :
   
config->load('recaptcha');
$public_key = $CI->config->item('recaptcha_public_key');
$private_key = $CI->config->item('recaptcha_private_key');
$response_field = $CI->input->post('recaptcha_response_field');
$challenge_field = $CI->input->post('recaptcha_challenge_field');
$response = recaptcha_check_answer($private_key,
$_SERVER['REMOTE_ADDR'],
$challenge_field,
$response_field);
if ($response->is_valid)
{
return TRUE;
}
else
{
$CI->validation->recaptcha_error = $response->error;
$CI->validation->set_message('recaptcha_matches', 'The %s is incorrect. Please try again.');
return FALSE;
}
}
}

6. Buat file recaptcha.php di folder config, tambahkan variable public dan private key yg didapat saat registrasi di re-CAPTCHA
   
$config['recaptcha_public_key'] = "...";
$config['recaptcha_private_key'] = "...";

7. Contoh implementasi di Controller
   
function testcaptcha()
{
$this->load->library('form_validation');
$this->load->helper('recaptcha');
$this->form_validation->set_rules('user', '%s harus diisi', 'trim|required|unique[users.username]');
$this->form_validation->set_rules('recaptcha_response_field', 'answer to the security question', 'required|recaptcha_matches');
$rules['user'] = 'trim|required';
if($this->form_validation->run())
{
echo 'SUKSESSS';
echo $this->input->post('user');
}else{
$this->load->view('testcaptcha');
}
}

8. Contoh di views nya :
   

Reference : http://codeigniter.com/forums/viewthread/94299/