Replace characters in a variable

[Troy Rollins]

If I have a variable with a known character, say ".", and I want to replace
everything after it with new characters - what is the proper syntax?

In this case, my variable holds a file name, and I want to change it's
extension. I've tried such things as getting the offset of ".", and then
putting empty into (chars > it), as well as a host of other approaches -
none of which worked.

Perhaps this is also another good "cookbook" thing.

-- 
Troy
RPSystems
www.rpsystems.net