EntityFieldQuery() example to return all published articles

entityfieldquery.php

<?php

/**
 * @file
 *   EntityFieldQuery demo.
 */
$query = new EntityFieldQuery();

// Return all articles that are published.
$result = $query->entityCondition('entity_type', 'node')
  ->entityCondition('bundle', 'article')
  ->propertyCondition('status', 1)
  ->execute();

// Print all nids to dd().
if (isset($result['node'])) {
  foreach (array_keys($result['node']) as $nid) {
    dd($nid);
  }

}