Script to reset customer password

mage_passwordreset.php

<?php
require_once 'app/Mage.php';
Mage::app();

$password = 'password01';
$customerId = 1;

$customer = Mage::getModel('customer/customer')->load($customerId);
$customer->setPassword($password);
$customer->setConfirmation($password);
$customer->validate();
$customer->save();