Drupal Console provides two types of commands, stand alone and container aware commands.
Stand alone commands: These commands can run outside of a Drupal 8 site root.
Container aware commands: These commands must be run within a Drupal 8 site root.
You can run Drupal Console from any directory on your system by using the --root option to define the Drupal root to be use in the command execution.
$ drupal --root=/var/www/drupal8.dev cr all
NOTE: Possible messages when executing Drupal Console outside a Drupal site root and no --root option provided.
When running the project outside of a Drupal 8 site root, the following message will be shown.
In order to list all of the available commands, you should run this inside a drupal root directory.
When running the project within of a Drupal 8 site root, but site is not yet installed, the following message will be shown.
In order to list all of the available commands you should install drupal first.
If you already have an existing Drupal 8 site and have installed the project globally using the instructions in 2.1 or 2.3, you will still need to install it into the Drupal site using the command 'composer require drupal/console:~1.0 --prefer-dist --optimize-autoloader'.