How to get the parameter from url in codeigniter?

$this->uri->segment(n); 

where n = 1 for controller, n = 2 for method and n = 3 for parameter and so on.
You need n = 3 to get parameter.
In your path localhost/log/job/php , your method name is missing.
Even if your method name is index then you route will be localhost/log/job/index/php
In case if you need to remove index.php from url then you will get parameter using localhost/log/index.php/job/index/php
To remove index.php you need to create .htaccess file by following these steps:

1. Create a .htaccess file where index.php file is located with content
   

   RewriteEngine on
   RewriteCond %{REQUEST_FILENAME} !-f
   RewriteCond %{REQUEST_FILENAME} !-d
   RewriteRule ^(.*)$ index.php/$1 [L,QSA]

2. Make sure that apache can access this .htaccess file. To do this edit apache configuration file. If you use ubuntu, then it is /etc/apache2/sites-available/default and then change AllowOverride none to AllowOverride all for directory and www directory.
   

      <Directory />
         Options FollowSymLinks
         AllowOverride all
      </Directory>
      <Directory /var/www/>
         Options Indexes FollowSymLinks MultiViews
         AllowOverride all
         Order allow,deny
         allow from all
      </Directory>

3. Then enable mod rewrite if you don't have it, with the following command:
   

       `sudo a2enmod rewrite`

4. Finally do not forget to restart apache.

Another Way:

$route['uri-(:any)/(:num)'] = "controller/function/$1/$2";

OR

$route['uri-(:any)'] = "controller/function/$1";

in your controller do some changes

<?php
 if (!defined('BASEPATH'))
   exit('No direct script access allowed');

 class controller extends CI_Controller 
 {
    function function($parameter1 = null, $parameter2 = null) 
    {
       ........
    }
 }