Encodings - which are effective for you?

[Steve8x8]

I'm struggling to understand how to use Encodings (which are in Ruby since 1.9), in particular their interaction with the various operating systems.
May I ask you to tell me:
- which OS you're using, and which locale ($LANG for Unixoids, forgot about Windows)
- the output of        ruby -v
- the output of        ruby -e 'p [Encoding.default_external, Encoding.default_internal]'
- the hex dump of  "äöü߀" if you can produce these characters within your command shell ("echo äöü߀ | hexdump -C" for Linux etc.)

Let me start:
- Debian Wheezy, LANG=en_US.UTF-8
- ruby 1.9.3p194 (2012-04-20 revision 35410) [i486-linux]
- [#<Encoding:UTF-8>, nil]
- 00000000  c3 a4 c3 b6 c3 bc c3 9f  e2 82 ac 0a