Drush can be run in your shell by typing "drush" from within any Drupal root directory.
$ drush [options] <command> [argument1] [argument2]
Use the 'help' command to get a list of available options and commands:
$ drush help
For even more documentation, use the 'topic' command:
$ drush topic
For multisite installations, use the --uri option to target a particular site. If you are outside the Drupal web root, you might need to use the --root, --uri or other command line options just for Drush to work.
$ drush --uri=http://example.com pm-updatecode
If you wish to be able to select your Drupal site implicitly from the current working directory without using the --uri option, but you need your base_url to be set correctly, you may force it by setting the uri in a drushrc.php file located in the same directory as your settings.php file.
$options['uri'] = "http://example.com";
Drush lets you run commands on a remote server, or even on a set of remote servers. Once defined, aliases can be referenced with the @ nomenclature, i.e.
# Run pending updates on staging site.
$ drush @staging updatedb
# Synchronize staging files to production
$ drush rsync @staging:%files/ @live:%files
# Synchronize database from production to dev, excluding the cache table
$ drush sql-sync --structure-tables-key=custom @live @devSee example.aliases.drushrc.php for more information.