Emmanuel Touzery wrote:
> 	I've been quick to write a Dir.up!() method (i was surprised it's not 
> standard?), however i'm having trouble with the Dir.root?() one.

There's File#dirname:

irb(main):004:0> File.dirname('/usr/local')
"/usr"

Dunno how well that works with drive letters, net shares, etc. on windows.