38, resp. 36 when using say instead of print

-nle@_[unpack'C*',$_]=/./g;@_=!print@_
[download]

Update:And 36 resp. 34:

-nle@_[ord]=$_,for/(.)/g;@_=!print@_
[download]

And if you're using the -E+say, you can shave off one more by leaving off the -l, at 33 strokes:

-nE@_[ord]=$_,for/(.)/g;@_=!say@_
[download]

Update2: And incorporating BrowserUk and JavaFan's ideas:

# 34 strokes on Windows, and also Unix if your shell doesn't treat "!"
+ special
-nE@_[map+ord,/./g]=/./g;@_=!say@_
[download]