% ri File.copy

------------------------------------------------------------- File::copy
      File::copy(from, to, verbose = false)
------------------------------------------------------------------------
      Copies a file +from+ to +to+ using #syscopy. If +to+ is a
      directory, copies +from+ to +to/from+. If +verbose+ is true, +from
      -> to+ is printed.

Yay!  That's what I want!

irb(main):001:0> File.copy("foo", "bar")
NoMethodError: undefined method `copy' for File:Class
         from (irb):1

*cry*

It turns out that File.copy is defined in 'ftools', but I have no idea 
how I'm supposed to know that.

Ben