Site aliases open a world of possibilities. They are one of the gems of Drush (and perhaps Drupal as well). The community built a lot of tools that rely on them and you can discover these at Drupal.org.

In this chapter, we covered practical examples with site aliases. We started by defining a site alias for our local Drupal project, and then went on to write a group of site aliases to manage remote environments for a hypothetical Drupal project with a development and production site. Before using site aliases for our remote environments, we covered the basics of setting up SSH in order for Drush to connect to these servers and run commands there.

We also learned that Drush automatically defines a set of special site aliases: @self, @none, plus one for each group of site aliases that we define. The @self alias means Bootstrap the current project, @none means Don't bootstrap the current project, and a group site alias such as @example means Run the command in all the sites defined within...