How to get id of any page in codeigniter controller -

i new in codeigniter.

how id of below page in codeigniter controller.

www.abc.com/about-us - page

www.abc.com/blog/hello-world - blog details page

www.abc.com/city - categories

www.abc.com/search - pass input field

please me.

code model this

<?php defined('basepath') or exit('no direct script access allowed');  class blog_model extends my_model {      public function __construct(){         parent::__construct();     } } ?> 

and controller like

<?php defined('basepath') or exit('no direct script access allowed');  class blog extends my_controller {      protected $per_page=1;     public function __construct(){         parent::__construct();         $this->load->model('blog_model');     }      public function index($page=1){         $page = $page-1;         if($page<0){             $page =0;         }         $where = ' status = ?';         $where_data = array(1);         $rs = $this->blog_model->__select('blogstablename','count(*) total_count', $where,$where_data);         $record = $rs->result();         $total_row = $record[0]->total_count;         $this->data['lists'] = $this->blog_model->__select('blogstablename','*',$where,$where_data,' blog_id desc',$page*$this->per_page,$this->per_page,3);         $this->load->view('template/header.php');         $this->load->view('template/navbar.php',array('active_tab'=>'blog'));         $this->load->view('blog',$this->data);         $this->load->view('template/footer.php');      } } ?> 

and in routes.php add line

$route['blog/(:any)'] = 'blog/index/$1';