sentinel/sentinel-dashboard/target/classes/resources/app/scripts/directives/sidebar/sidebar-search/sidebar-search.html

<li class="sidebar-search">
  <div class="input-group custom-search-form">
    <input type="text" class="form-control" ng-model="searchApp" placeholder="Search...">
    <span class="input-group-btn">
      <button class="btn btn-default" type="button">
        <i class="fa fa-search"></i>
      </button>
    </span>
  </div>
</li>