You can do this with just one regex:

use strict; use warnings;
my $input = "'C-3PO' or 'See-Threepio' is a humanoid robot character f
+rom the [[Star Wars]] universe who appears in the original ''Star War
+s'' films, the prequel trilogy and the sequel trilogy.";
my $regex = qr/('|\[\[|\]\])/;
$input =~ s/$regex//g;
print $input;
[download]