The Ruby doc states the following for a String#=~

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

When I run what looks like the same command, I get the following error.

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

I have tried this on a couple of different environments but always
Ruby 1.8.4. Can anyone provide me with any insight as to why I don't
get the nil return value?

tim