Search and replace text using Views Bulk Operations

search_and_replace.php

<?php

/**
 * Search and replace using Views Bulk Operations
 */
$node = node_load($entity->nid); //load node form entity supplied by VBO  

$haystack = $node->body['und'][0]['value']; //set node body to be haystack
$search = "Office of International Students and Scholars"; //Set the string to search for
$replace = "International Student & Scholar Services"; //String to replace target

$pos = strpos($string, $search);
//test if the string exists before attempting to replace
if ($pos != false) {
  drupal_set_message(l($node->title, 'node/'.$entity->nid)); //link to node with change
  $node->body['und'][0]['value'] = str_replace($search, $replace, $haystack);
  node_save($node);
}