Drush is decoupled from Drupal. This means that it does not necessarily need a Drupal site to work with. Some commands do require a Drupal project to bootstrap, while for others, this might be optional. Let's take core-status as an example. This command gives us information about the current context. If we run this command outside of a Drupal project, we will obtain configuration details for Drush and our local environment:
$ cd $HOME $ drush core-status PHP executable : /usr/bin/php PHP configuration : /etc/php5/cli/php.ini PHP OS : Linux Drush version : 7.0.0-alpha5 Drush temp directory : /tmp Drush alias files :
Now, if we change directory to a Drupal project, we will get extra information about it:
$ cd /home/juampy/projects/drupal $ drush core-status Drupal version : 7.29-dev Site URI : http://default Database driver : mysql Database username : root Database name : drupal7x Database : Connected Drupal bootstrap : Successful Drupal user : Default theme : bartik Administration theme : seven PHP executable : /usr/bin/php PHP configuration : /etc/php5/cli/php.ini PHP OS : Linux Drush version : 7.0.0-alpha5 Drush temp directory : /tmp Drush alias files : Drupal root : /home/juampy/projects/drupal Site path : sites/default File directory path : sites/default/files Temporary file directory path : /tmp
In the preceding scenario, Drush finds out that it is currently at the root of a Drupal project that uses the default location to store its settings (sites/default). Therefore, it is able to bootstrap Drupal and load its configuration.