track changes in an RTF?

[-]

In terminal there is a nifty application called textutil.  It can convert 
one text format into another.

To use it is very simple:

textutil -convert format filename

The format is the desired format, so the document in question would be if 
one wanted a "doc" file from the "rtf" file.

textutil -convert doc filename.rtf

It handles these formats:

(txt, rtf, rtfd, html, doc, docx, odt, wordml, or webarchive)



XB