Drush is a command line shell and scripting interface for Drupal. It is used to manage and administer Drupal websites from the command line. Drush can be used to perform a variety of tasks, such as installing and updating modules, downloading and enabling themes, running database updates, and more. Drush is an essential tool for any Drupal developer or administrator.

Drush is written in PHP and is distributed as a command line tool. It is available for both Linux and Windows operating systems. Drush is installed on the server where the Drupal website is hosted. It can be used to manage multiple Drupal websites from the same server.

Drush commands are written in the form of a command line argument. For example, to install a module, the command would be “drush dl [module name]”. Drush also provides a number of helpful commands for managing Drupal websites, such as “drush cc all” which clears the Drupal cache, or “drush up” which updates all installed modules.

Drush is an invaluable tool for managing Drupal websites. It is fast, efficient, and easy to use. It can save time and effort when managing multiple Drupal websites, and is an essential tool for any Drupal developer or administrator.