Excuse the newbie question. Given the following string: 
my $string = 'fred=abcdef&wilbur=123456&fred=hijk';

[download]
The following code catches all cases except for the last. 
sub obscure {
   my ($self, $s) = @_;
   use constant REPLACEMENT => '*';

   my @tags = qw/fred wilbur/;

   for my $tag (@tags) {
       $s =~ s{$tag=(.*?)\&}{
          "$tag=" . (REPLACEMENT x length($1)) . '&'
       }gex;
       $s =~ s/$tag=(.*)$/"$tag="/gex;  # WRONG
   }

   return $s;
}

[download]
How do I write the second substitution to catch the end-of-line case? Thanks.

In reply to edge case in substitution? by Anonymous Monk

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