Another of those things that seem so hard to find. Apparently CFMX uses the ORO libraries for the regular expression handling.
"CF MX RegExp engine is based on the ORO libraries"
If that is true, then here is a link to the ORO library home page:
Get only numbers from a string with regex: tempstring = rereplace(tempstring, '[^0-9]+', '', 'all'); (source: http://www.houseoffusion.com/groups/regex/thread.cfm/threadid:51)
Allow a-z small caps, A-Z upper case, 0-9, and "-": [^a-zA-Z0-9-]
Replace all characters in a string that aren’t numbers, letters, or underscores with an underscore:
tags: cfml, coldfusion,