What does Drush error "Unknown option: --db-url" mean? Somehow user 1 has become blocked on a Drupal site I manage.   As a result, I can't issue a uli command via Drush.  I tried to use the command 

drush @pantheon.xxxxxx.dev user-unblock --uid=1


but it returns error 

Unknown option: --db-url.  See `drush help user-unblock` for available options.  


I have checked the help for user-unblock for but it does not mention --db-url.  The site is working and and other users can log in, however I can't get in as admin.  

Thanks.
Pantheon site aliases are only compatible with Drush 5. I had the same message when trying to use Drush 6.

On a Mac with Homebrew, I ran "brew install drush5" and then symlinked the resulting file (/usr/local/Cellar/drush5/5.9/libexec/drush) to "/usr/local/bin/drush5" not to interfere with my existing Drush installation.

Now I can run commands such as "$ drush5 @pantheon.xxx uli" when needed for Pantheon.