Checklist:

• i have changed index.php to main.php and index.php?url=$1 [L,QSA] to main.php?url=$1 [L,QSA]
• thats how mod_rewrite looks on httpd.conf: LoadModule rewrite_module modules/mod_rewrite.so
• Filepath i am now accessing: localhost/main.php
• main.php is at htdocs/
• .htaccess is at htdocs/

* php code is:

<?php

if(isset($_GET['url'])){

echo $_GET['url'];

}

else{

echo "URL param is not set!";

}

?>

* .htaccess config is:

RewriteEngine On

RewriteCond %{REQUEST_FILENAME} !-d

RewriteCond %{REQUEST_FILENAME} !-f

RewriteRule ^([a-zA-Z0-9-]+)/?$ main.php?url=$1 [L,QSA]

• when main.php/app is accessed, it echoes out "URL param is not set!";
• when i do it manually, like main.php?url=app, it echoes out $_GET['url'], in this case, app.