printing all running session variable in laravel 5.1

dd(session()->all());

$data = session()->all();

$sessions=session()->all();

$sessions=Session::all();

foreach($sessions as $k=>$v){
    echo $k."=".$v." ";
}
//or use : 
dd(session()->all()) ; // this is  var_dump equeivelent

$user_id = session('user_id'); // key : user_id