Get all Magento categories.

get_all_categories.php

<?php
  $categories = Mage::getModel('catalog/category')->getCollection()
  ->addAttributeToSelect('id')
  ->addAttributeToSelect('name')
  ->addAttributeToSelect('url_key')
  ->addAttributeToSelect('url')
  ->addAttributeToSelect('is_active');
  
  foreach ($categories as $category)
  {
      if ($category->getIsActive()) { // Only pull Active categories
          $entity_id = $category->getId();
          $name = $category->getName();
          $url_key = $category->getUrlKey();
          $url_path = $category->getUrl();
      }
  }
?>