Clear Magento cache/reindex

Question

How to clear Magento cache/reindex programmatically?

Answer 1

<?php
// clear cache
Mage::app()->removeCache('catalog_rules_dirty');
// reindex prices
Mage::getModel('index/process')->load(2)->reindexEverything();
/*
1 = Product Attributes
2 = Product Attributes
3 = Catalog URL Rewrites
4 = Product Flat Data
5 = Category Flat Data
6 = Category Products
7 = Catalog Search Index
8 = Tag Aggregation Data
9 = Stock Status
*/
?>