I sure would not try cat on a rar file, rar by default does compress the file but even without compression a rar file contains extra overhead data, it is never simply a file split into parts.

Another very handy open sores tool that does deal with rar files is 7-zip. However, I don't believe it is on the Live CD and I don't know of any rar utility on the CD (although there certainly could be one hiding there some where).

It should be obvious that no utility that deals with rar file under Linux will begin with "Win", at least none that run natively.