This UNIX software package has been run upon all known operating systems at some time or another. This includes Linux, FreeBSD, SunOS, Solaris, HP-UX and AIX. Various versions of the above operating systems are supported, although testing is limited to those available at any given time for a specific version. An authorised user is enabled to obtain any specified users OS identity (including root) if the inbuilt checks are validated. The latest version is 3.3.