How can I log in as any given user with Drush?
You can log in to any Drupal site if you have access to the command line and Drush, knowing either the username

$ drush uli username --no-browser


OR the user ID.

$ drush uli --uid 123 --no-browser


This will return you an URL that you can copy paste into your browser address bar and login as that user. You can leave out the --no-browser option when you want the command to directly launch the browser.