or download this
;; Use cperl-mode instead of the default perl-mode
...
(add-to-list 'interpreter-mode-alist '("perl" . cperl-mode))
(add-to-list 'interpreter-mode-alist '("perl5" . cperl-mode))
(add-to-list 'interpreter-mode-alist '("miniperl" . cperl-mode))