1) You can edit errors such as you made here (by failing to include code tags) by updating (adding code tags) rather than by duping the question, as you did in id:/543444. Please update, rather than creating a new question, in the future. On the other hand, until we fix the the dupe situationdone please see chromatic's response to your other post, in case you're showing us historical output: did you reinstall or update perl recently?

2) If the your illustration is not suffering from fatfingers or editing, what is not working? I see cat spitting out plausible code with a perfectly fine shebang --
#!/usr/bin/perl -W
... and execution of hello.pl emitting what I would expect from your code.