How to manipulate strings using Regular Expressions?

try this

<cfset resourcename="tets\sdgg  fjsjd/">
<cfoutput>#ReReplace(resourcename,"[\\ /]","_","ALL")#</cfoutput>

I agree with TLC-IT that in many cases regular expressions can be more trouble than they're worth, but in this particular instance the expression needed is simple enough that it would simplify the code a bit - especially down the road if you run across other characters that need to be replaced.  The code would look something like this: <cfset string = reReplaceNoCase(trim(arguments.queryObject[item]),"[\s\\/]","_","all") />

Sure!  You can "name that tune" in just one line...  but is it worth the effort?  I mean, "one line vs. two?"

(He continued, quietly putting on his Perl hat... neatly embroidered  "TMTOWTDI")

If you do want to do it, even as just an exercise in frustration , then regular-expressions are the right tool to use.  REReplaceNoCase() is, indeed, the function you want.  A regular-expression can be written which matches, as you say, "blank spaces, slashes ("/" and "\"), etc."  Then you use the function to replace "all" occurrences with an underscore.

Now, having said that ... "never mind what is 'efficient.'  What is abundantly clear?"  The regular expression would indeed be "clear enough," but the difference between "one" and "a few" lines-of-code might be, literally, not worth the time.  Your call.

REReplaceNoCase()