A variable can contain a regular expression, metacharacters and all, so you are correct about what perl is doing here: it's interpreting the dollar sign as the indicator for end-of-line.

You can get the behavior you want by using \Q (quote) and \E (end, I guess). \E is optional:

if ($after =~ /\Q$scur/){ ...
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You can read more about this in perldoc perlre.

(2004-05-20 fixed typo that swapped \U for \E)