Script to duplicate a target category along with it's sub-categories and products under another category.

clonecategory.php

<?php //can be run as root script
 
require '../app/Mage.php';
Mage::app()->setCurrentStore(Mage_Core_Model_App::ADMIN_STORE_ID);
 
 
    $categoryId = 864; //Target Cat to copy
    $baseCategoryId = 240; //Category to appear under
 
    $category = Mage::getModel('catalog/category')->load($categoryId);
    $defaultCategory = Mage::getModel('catalog/category')->load($baseCategoryId);
    duplicate($category, $defaultCategory, 1);
 
 
function duplicate($categoryToClone, $parentCategory, $level)
{
    // This will clone the clild and assign it to the new parent
    $newCategory = clone $categoryToClone;
    $newCategory->setPath($parentCategory->getPath())
        ->setParentId($parentCategory->getId())
        ->setId(null);
 
    // Assign all products from the cloned category to the new
    $newCategory->setPostedProducts($categoryToClone->getProductsPosition());
 
    $newCategory->save();
 
    // Applies the changes to the subcategories infinite levels
    $subcategories = $categoryToClone->getChildrenCategories();
    if (count($subcategories) > 0) {
        foreach ($subcategories as $subcategory) {
            duplicate($subcategory, $newCategory, ++$level);
        }
    }
}
?>