how to remove sessions in Laravel 5

You should use this method

 Route::get('/logout', function() {
 Session::forget('key');
  if(!Session::has('key'))
   {
      return "signout";
   }
 });

You can try with Session::pull('key');

And if you want to delete all sessions variable you can use Session::flush();

http://laravel.com/docs/5.0/session#session-usage

    namespace App\Http\Controllers;

    use Illuminate\Http\Request;

    use App\Http\Controllers\Controller;

    class StudentRecord extends Controller
       {

    public function logout(Request $req)
        {
     if($req-session()->has('key'){
              $req->session()->forget('key');
        return redirect('/');
              }

//Or simple
    public function logout(Request $req)
        {
     //if($req-session()->has('key')
         $req->session()->flush();
         }


    }


    //Then Do this in your route file
      Route:get("/logout",StudentRecord@logout);

        <a href=" {{ url(logout)}}">logout</a>