Use Drush to update multi-site setup I have a multi-site setup where 3 different sites share the same codebase.  All of the modules are in the all/modules folder so they all have the exact same modules.  I want to update the modules and core for the codebase with drush but I can't find a way to do it.

There is no settings.php file in sites/default so drush is throwing an error.  Do I need to just create a dummy database so drush can connect and update the modules? Obviously I will have to run update.php on the sites after the updates are made.

The databases are separated, they just share modules and core.
Instead of applying the updates to each individual site by using @sites which never worked, I was able to achieve it by running the updates on one specific site. Here is the code that worked for me:

drush -l example.com pm-update

example.com being the name of my symlink.  Side note: I did not have to create a drush alias for this to work.