Input Error in Linux : Undefined property: Welcome::$input

I am learning codeigniter. I am watching a course videos in udemy. I wrote the codes in the video. CODES ARE WORKING ON WINDOWS BUT NOT WORKING IN LINUX   Please help me.


Controller :

Code:

class Welcome extends CI_Controller {

    public function __construct()
    {
        parent::__construct();

    }

    public function index()
    {

        $this->load->view('form');

    }

    public function save(){
        
        echo $this->input->post("name");
    }
    
}

View :

Code:

<form action="<?=base_url("Welcome/save")?>" method="post">

    <input type="text" id="fname" name="name"><br>
    <button type="submit">Gönder</button>
</form>