gistfile1.php

<?php
/*
 * Add this code to your theme's functions.php file
 */
 
// Theme activation
add_action("after_switch_theme", "theme_activated");
function theme_activation_hook(){
    error_log('theme activated');
}

// Theme deactivation
add_action('switch_theme', 'theme_deactivated');
function theme_deactivation_hook () {
    error_log('theme deactivated');
}