cli

change your directory to Magento root then execute this command

php -r 'require "app/Mage.php"; Mage::app()->getCacheInstance()->flush();'

First of all you need to change the directory to  shell folder under magento root

{Magento root}/shell

Checking for the status of all indexes

php indexer.php --status

Re-indexing a single index
Each index has its own index key that you can use to reference it when asking Magento to re-index. To get these keys, you can use the following command:

php indexer.php --info