Simple Login and Logoff Link for WordPress

header.php

<?php
/*
*
* This checks if user is logged in
* If Logged in display logout link else display login link
* Also note the redirects to the login page and the home page.
*
*/

<?php if (is_user_logged_in()) : ?>
  <a href="<?php echo wp_logout_url(site_url( '/login/ ' )); ?>">Logout</a>
<?php else : ?>
  <a href="<?php echo wp_login_url(home_url()); ?>">Login</a>
<?php endif;?>