Drush is a command-line shell interface for Drupal. It lets you do almost anything you would do through the Drupal admin interface — enabling modules, clearing caches, running cron, backing up the site — all from the terminal.
Installation
The preferred way to install Drush is via the official PEAR channel, but it can also be installed manually on a shared server.
Backup and restore
archive-dump backs up the codebase, files, and database into a single file:
drush archive-dump
drush archive-restore
Common commands
drush pm-download
drush pm-enable
drush pm-disable
drush cc all
drush cron
drush sql-dump
drush uli
Enjoy!