login 1:4.2-3.1ubuntu5.3 (armhf binary) in ubuntu xenial

 These tools are required to be able to login and use your system. The
 login program invokes your user shell and enables command execution. The
 newgrp program is used to change your effective group ID (useful for
 workgroup type situations). The su program allows changing your effective
 user ID (useful being able to execute commands as another user).