http://ruby-doc.org/core/classes/String.html#M001849 says this:

   "cat o' 9 tails" =~ '\d'   #=> nil

I get this:

irb(main):001:0> "cat o' 9 tails" =~ '\d'
TypeError: type mismatch: String given
         from (irb):1:in `=~'
         from (irb):1

$ ruby -v
ruby 1.8.4 (2005-12-24) [i386-mswin32]

Any clues?

-- 
Alex