RiTrainer.app is a small toy application that allows you to type in RIB commands and instantly have them rendered (with Quick RenderMan). It can't open or save files, but cut & paste work just fine. :-)
RiTrainer.compressed is available for ftp at geom.umn.edu in /pub.
This app was originally written for my own personal use, but people here at the Center have found it useful, so I thought others might as well.