function excerpt($limit) {
  $excerpt = explode(' ', get_the_excerpt(), $limit);
  if (count($excerpt)>=$limit) {
    array_pop($excerpt);
    $excerpt = implode(" ",$excerpt).'...';
  } else {
    $excerpt = implode(" ",$excerpt);
  }
  $excerpt = preg_replace('`\[[^\]]*\]`','',$excerpt);
  return $excerpt;
}