Codeigniter URL Routing Issue

I'm new to codeigniter and want to set my URLs on website currently I'm using version 3.0.1 URL looks like

http://oti.nhmp.net/index.php/site/about_us

I want it like this

http://oti.nhmp.net/about_us

i have tried URL routing in routes file but it's not working for me here is the code

routes.php

$route['default_controller'] = 'site';
$route['about_us'] = "index.php/site/about_us";
$route['404_override'] = '';
$route['translate_uri_dashes'] = FALSE;

.htaccess

<IfModule mod_rewrite.c>

    RewriteEngine On
    RewriteBase /

    #Removes access to the system folder by users.
    #Additionally this will allow you to create a System.php controller,
    #previously this would not have been possible.
    #'system' can be replaced if you have renamed your system folder.
    RewriteCond %{REQUEST_URI} ^system.*
    RewriteRule ^(.*)$ /index.php?/$1 [L]

    #When your application folder isn't in the system folder
    #This snippet prevents user access to the application folder
    #Submitted by: Fabdrol
    #Rename 'application' to your applications folder name.
    RewriteCond %{REQUEST_URI} ^application.*
    RewriteRule ^(.*)$ /index.php?/$1 [L]

    #Checks to 
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteRule ^(.*)$ index.php?/$1 [L]    

</IfModule>

<IfModule !mod_rewrite.c>
    # If we don't have mod_rewrite installed, all 404's
    # can be sent to index.php, and everything works as normal.
    # Submitted by: ElliotHaughin

ErrorDocument 404 /index.php

</IfModule>




Answer:

You have to read user guide carefully.

Add .htaccess

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

Remove index.php from application/config.php

$config['index_page'] = '';//line 32

And last but not least. You have to decide how is your application gonna work. If you want to route any request with one string to one controller for example: Page.php, you have to add such line in application/routes.php

$route["(:any)"] = "page";

Or you can make controller About_us.php .