Helper for dev in wordpress

show_current_template.php

<?php
function show_current_template($wp_admin_bar)
{
    global $template;
    $args = array(
    'id' => 'current_template',
    'title' => basename($template),
    'meta' => array('title' => $template),
  );
    $wp_admin_bar->add_node($args);
}
if (current_user_can('manage_options') && !is_admin()) {
    add_action('admin_bar_menu', 'show_current_template', 9999);
}