rewriting-the-search-url

add_action( 'template_redirect', 'fb_change_search_url_rewrite' );
function fb_change_search_url_rewrite() {
	if ( is_search() && ! empty( $_GET['s'] ) ) {
		wp_redirect( home_url( "/search/" ) . urlencode( get_query_var( 's' ) ) );
		exit();
	}
}

add_filter('rewrite_rules_array','hp_myRewrites');
function hp_myRewrites( $rules )
{
    $newrules = array();
    $newrules['author/([0-9]+)/?'] = 'index.php?pagename=author&author_ID=$matches[1]';
    $newrules['search/(.?.+?)/page/([0-9]+)/?'] = 'index.php?s=$matches[1]&paged=$matches[2]';
    $newrules['(.?.+?)/([0-9]+)/page/([0-9]+)/?'] = 'index.php?category_name=$matches[1]&post_year=$matches[2]&paged=$matches[3]';
    $newrules['(.?.+?)/page/([0-9]+)/?'] = 'index.php?category_name=$matches[1]&paged=$matches[2]';
    $newrules['(.?.+?)/([0-9]+)/?'] = 'index.php?category_name=$matches[1]&post_year=$matches[2]';
    return $newrules + $rules;
}