This tool determines whether an RFC file contains an published or unpublished document. In case the file does not contain anything or does not exist, "empty" is returned.
getidtype rfcnnnn.txt ...
% getrfctype rfc1000.txt rfc3500.txt rfc1000:published rfc3500:notissued
The tool can be downloaded here. Current version is 2.0.1. See also getauthors.
This software was written by Jari Arkko and its use and modification is free. No warranty is given: use this software at your own risk.