To clean it out, we decided the best course of action would be deleting every account except those with admin privileges, because most of the real humans were in the admin group and those who weren’t could get the project leader to re-add their accounts. I was familiar with the Vim command :d/pattern/g to delete all lines containing a pattern, but this time I needed to delete all lines that didn’t have ‘admin’ in them. Instead, since I know all the users in the admin group have their group permissions in the form “admin,user,” the command that removed everyone except the admin users was :v/admin,user/d .