Drush is a powerful utility that significantly reduces the number of routine actions when working with CMS Drupal. Installing Drupal requires downloading a significant number of modules from different sections of drupal.org, drush allows you to download all modules with a single command,
$ drush dl cck views token admin_menu
and another command to include them:
$ drush en cck views token admin_menu
Update modules: ')
$ drush update
To install drush, download and unpack the archive and use it via ssh.
Also with the help of drush you can synchronize the developed site and database with the main site.