Well, for one thing, what pops up is going to depend on what's in $HTMLLine to begin with. (which is a roundabout way of asking what your data is!). What's the input? Does it come from an HTML file?

Let's take a look at the regex and see if we can't tease out what the regex will do (whatever it was *intended* to do, we don't know ... but we might get a better idea by finding out what it does do!)

• s/\$ match a literal "$" character, followed by ...
• ([a-zA-Z_0-9\[\]{}'+) one or more of any letter, digit, underscore, [, ], {, }, or ', and store the results in $1
• /${$1}/ REPLACE that with with the contents of $1 enclosed by curlies with a literal $ at the front.

For example, this regex will replace each occurrence of something like $foo_bar with ${foo_bar}

Looking at it, the regex is designed to allow you to encase Perl variable names in curlies (but it won't quite do that, because the single quote isn't a valid part of a Perl variable name ... unless this is an oddity of the fact that colons in package names get translated to single quotes? I'm fuzzy on such details, wait for guru guidance on that part of the issue ...); you would usually want to do this inside of double-quote contexts, because

print "$foo_bar"
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print "${foo}_bar"
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HTH

Philosophy can be made out of anything. Or less -- Jerry A. Fodor

Well, it wouldn't work for things other than scalars. To make it work, change it to:

s/(\$[\w\[\]{}']+)/$1/gee;
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Update: Well, ${array[0]} actually is the same as $array[0]. My replacement also works OK, but they both fail for strings like q(${name}'s).

Update: I was thinking that the FAQ had a method using eval which is pretty dangerous. I checked and that was mentioned in a post here, not in the FAQ. But that method has another problem in that it is hard to pick a delimiter to use in eval '"'.$str.'"' (since $str might contain a " or any other delimiter you pick).

Well, it appears that my solution comes close to dealing with these problems, so I made it more robust:

s/(\$[\w\[\]{}']+)/'"'.$1.'"'/gee;
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Looks like you're trying to expand a variable in a text string. This is a faq (see How can I expand variables in text strings?).

Turn on warnings (you'll probably get a lot of "Use of unitialized value" messages, which is probably what your problem is) or, even better, migrate to a more robust templating system like Template Toolkit, Text::Template or HTML::Template.