Package cmdline is a part of Tcllib. Documentation can be read online at http://tcllib.sourceforge.net/doc/cmdline.html , and examples of cmdline usage appear in ftpd, htmlparse, and pop3.
Glenn Jackman offers http://groups.google.com/groups?th=89144039acd5554b#link5 and http://groups.google.com/groups?th=84e714d1329a035#link5 as "examples of cmdline in action".
Category Package a subset of Tcllib.