I am working on a CGI script where I need to take some user input, clean it, and redisplay it on a Web page. To eliminate a security concern, I am taking dangerous characters and converting them to their character code equivalent (e.g. & = & #38; -- All characters codes in this example have an extra space after the first ampersand to guarantee that they are not converted when displayed). Unfortunately, this winds up with hideous monstrosities like the following: 
s/(&|;)/($1 eq "&")?"& #38;":"& #59;"/ge;

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This substitutes the appropriate character code for either the ampersand or semicolon as it encounters it in the variable. I have to do both on the same line since the character codes themselves contain ampersands and semicolons and substituting for one would create false positives for the other is the other was substituted for later. While I'm rather proud of that regex (for a newbie), I have to admit that it's not terribly clear. Is there an easier way to scrub incoming data that will be tossed out to a Web page later on?

In reply to Safer (and cleaner) way to print user-supplied text. by Ovid

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