Elixir interpreter error -

i following elixir getting started says run:

iex> 'hello' 

so ran:

iex(1)> 'hello' 

and got:

 ** (compileerror) iex:2: undefined function i/1 

elixir version:
erlang/otp 18 [erts-7.3] [source] [64-bit] [smp:4:4] [async-threads:10] [kernel-poll:false] interactive elixir (1.1.0-dev)

the function iex.helpers.i/1, guide linked uses, was added in elixir 1.2.0. need install elixir 1.2.0 or later version use it.

see http://elixir-lang.org/install.html#unix-and-unix-like, installation guide.