On a VPS I own (hosted at bluevm.com), I have three users: userone, with password foo, and sudo rights. usertwo, with password bar, without sudo rights. root, with now password (deleted with passwd ...
I'm curious if there is a way to enable one user to login (via su) into another user, without needing to know that users password. For instance, if I'm logged in as user1, I would like to give user2 ...