Mass update nodes in drupal

mass_update_nodes_devel.php
<?php
module_load_include('inc', 'node', 'node.admin');
$nids = db_query("SELECT nid FROM {node} where type = 'bill' ")->fetchCol();

// Update in batches
$start = 0;
$batch_size = 10;
$nids = array_slice($nids, $start, $batch_size);
node_mass_update($nids, array());