how create and display data with php session code example

Example 1: destroy session php

<?php 
 session_start(); // start session
 session_destroy();  // Delete whole session
// OR
unset($_SESSION['username']); // delete any specific session only
?>

Example 2: php session variables

<?php
   session_start();
   $_SESSION['var'];
?>

Example 3: can we acces session variable in two files

<?php
  session_start();

  ...

  if($responseCode == 1) {
    $_SESSION['card_id']    = $_POST['card_id'];
    $_SESSION['password']   = $_POST['password'];
    print '<script type="text/javascript">'; 
    print 'window.location = "http://domain.com/File2.php";';
    print '</script>';
  }
?>