Delete all tags of a WP install

delete-all-tags.php

<?php

/**
 * Delete all tags of a WordPress blog
 *
 * @author Ashfame
 *
 * Place this file in root of your WordPress install and open it in the browser - domain.com/delete-all-tags.php
 */

echo '<h1>Delete all tags</h1>';

require 'wp-load.php';

echo '<h2>WordPress loaded</h2>';

$tags = get_tags( array( 'number' => '', 'hide_empty' => false ) );

if ( !empty( $tags ) ) {
	echo '<ul>';
	foreach ( $tags as $tag ) {
		wp_delete_term( $tag->term_id, 'post_tag' );
		echo "<li>Deleted \"{$tag->name}\" which had the ID {$tag->term_id} and had {$tag->count} posts in it.</li>";
	}
	echo '</ul>';
	echo 'All done!';
} else {
	echo '<p>Nothing to delete!</p>';
}