For some reason I find myself rewriting this little bit of code every time I need to update a bunch of nodes on a site. Going to post it here to save myself some time. Be aware that this might time out if you've got a large number of nodes, designed for up to a couple hundred nodes:
<?php
// TODO: Set your basic criteria here:
$result = db_query("SELECT n.nid FROM {node} n WHERE n.type = '%s'", array('task'));
while ($row = db_fetch_array($result)) {
$node = node_load($row);
if ($node->nid) {
$node->date = $node->created;
// TODO: Test and set your own value here:
if (empty($node->field_task_status[0]['value'])) {
$node->field_task_status[0]['value'] = 'active';
$node = node_submit($node);
node_save($node);
drupal_set_message(t('Updated <a href="!url">%title</a>.', array('!url' => url('node/'. $node->nid), '%title' => $node->title)));
}
}
}
?>