One of the indispensible tools for developing in Drupal is Drush. It allows you to interact with modules, users, configuration, caches, and more through the command line, faster than going through the user interface in a web browser. In order to use Drush with Drupal 8, you need to be running the latest stable version of Drush, Drush 8. There are several new features in Drush 8 that make development easier.
The largest is the inclusion of the PsySH REPL to do quick experiments using a bootstrapped version instance of Drupal. Running drush php will open up a command shell where you can directly interact with the Drupal API.
