Magento Useful paths

Getting Magento path :

1) Mage::getBaseDir();
 Return output : /var/www/html/yourwebsite

2) Mage::getBaseDir('app')
 Return output : /var/www/html/yourwebsite/app

3) Mage::getBaseDir('media')
 Return output : /var/www/html/yourwebsite/media

4) Mage::getBaseUrl('js')
Return output : http://yourwebsite.com/js/

5) Mage::getBaseUrl('skin')
Return output : http://yourwebsite.com/skin/