showkey equivalent on mac os x?

I'm debugging an emacs keyboard bi开发者_StackOverflownding on my mac (C-/ to undo, if you're curious), and I came across a suggestion on EmacsWiki that I could use "showkey" to find the scancode. But it looks like a GNU/Linux-only kinda thing. Didn't find it on MacPorts. Anyone know of an alternative or something I'm missing?

Key Codes may be what you're looking for generally, even if you're out of luck with C-/.

The emacs-app port works well if you need to escape from Terminal.app

Showkey's home page is http://catb.org/esr/showkey/.

FYI, if you're using Terminal.app, there's something of a known issue that C-/ is broken and doesn't get sent through to underlying applications. iTerm.app doesn't have that issue.