Try changes your substitution to 
$source =~ s/\Q$complete\E/<a href='$url'>$title<\/a>/g || print "

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The "\Q" puts backslashes in front of all the special characters in '$complete'. This will make the regex treat them literally instead of a as metacharacters.

In reply to Re: replacing variable in regex - probs with special chars? by fletcher_the_dog
in thread replacing variable in regex - probs with special chars? by Emanuel

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