How to anonymise user names and emails?
I came up with this:

drush sql-query "
  UPDATE users 
  SET 
    name=CONCAT('User-',uid),
    mail=CONCAT(uid,'@anon.com'), 
    init=CONCAT(uid,'old@anon.com') 
  WHERE uid &gt; 0;"
drush upwd User-1 --password=SecureAdminPassword