cgi revisited

[BCE]

Would anyone care to elaborate a little on using rev as a faceless cgi on OS
X?  I know that the lastest user tip on the Rev site discusses it, but I
have 2 questions:

1. - Do you name the actual script with an extension? (ie, ".cgi")
2. - If using the Darwin engine, then do you use

"#!/Library/Webserver/Cgi-Executables/Darwin 2"

as the opening line of the script?

All I want to do is a simple "Hello World" type of script, just to test this
out.  It doesn't seem to work as of yet.

Thanks!

Mark