I found some of the Etc functions missing which are mentioned in
Matsumoto’s book “Ruby in a nutshell”, for example Etc.dir and OTOH, exists (for example):

irb(main):002:0> Etc.dir
NoMethodError: undefined method dir' for Etc:Module from (irb):2 irb(main):003:0> => "Etc" irb(main):004:0> NoMethodError: undefined methodshell’ for Etc:Module
from (irb):4
from :0

I’m running the following Ruby version:

$ irb --version
irb 0.9.5(05/04/13)
$ ruby --version
ruby 1.8.4 (2005-12-24) [i686-linux]

As the book was published 2001, it can’t be that I just have an
outdated Ruby version.

What am I doing wrong here?