Drush @sites alias does not work in a multisite installation I have 3 Drupal sites installed and I've developed a simple "hello-world" command that just does the following:

drush_log(getmypid() . ' Hello world!', 'ok');


When I run drush @sites hello-world I get the following error message:


  Could not find a Drupal settings.php file at sites/default/settings.php


Please note that the command is working fine when run for a specific site.

drush -l test1 hello-world


I was under the assumption that Drush @sites alias should be available by default. Is it not?
I just tested this on HEAD of today's master branch of drush, and drush @sites status worked fine for me with no sites/default folder.  Try upgrading to drush 7.0-alpha9.