% cat lib/hola.rb 
  class Hola 
   def self.hi 
    puts "Hello world!" 
   end 
  end 

  % cat hola.gemspec 
  Gem::Specification.new do |s| 
   s.name    = 'hola' 
   s.version   = '0.0.0' 
   s.date    = '2010-04-28' 
   s.summary   = "Hola!" 
   s.description = "A simple hello world gem" 
   s.authors   = ["Nick Quaranto"] 
   s.email    = 'nick@quaran.to' 
   s.files    = ["lib/hola.rb"] 
   s.homepage  = 
    'http://rubygems.org/gems/hola' 
  end 

  % gem build hola.gemspec 
  Successfully built RubyGem 
  Name: hola 
  Version: 0.0.0 
  File: hola-0.0.0.gem 
   
  % gem install ./hola-0.0.0.gem 
  Successfully installed hola-0.0.0 
  1 gem installed 

  % irb 
   require 'hola' 
  => true 
   Hola.hi 
  Hello world! 

  $ curl -u tom https://rubygems.org/api/v1/api_key.yaml > 
  ~/.gem/credentials 
  Enter host password for user 'tom': 

  % gem push hola-0.0.0.gem 
  Pushing gem to RubyGems.org... 
  Successfully registered gem: hola (0.0.0) 

  % tree 
  . 
  ├── hola.gemspec 
  └── lib 
    ├── hola 
    │  └── translator.rb 
    └── hola.rb 

  % cat lib/hola/translator.rb 
  class Hola::Translator 
   def initialize(language) 
    @language = language 
   end 
   
   def hi 
    case @language 
    when :spanish 
     "hola mundo" 
    else 
     "hello world" 
    end 
   end 
  end 

  % cat lib/hola.rb 
  class Hola 
   def self.hi(language = :english) 
    translator = Translator.new(language) 
    translator.hi 
   end 
  end 
   
  require 'hola/translator' 

  % cat hola.gemspec 
  Gem::Specification.new do |s| 
   s.name    = 'hola' 
   s.version   = '0.0.0' 
   s.date    = '2010-04-28' 
   s.summary   = "Hola!" 
   s.description = "A simple hello world gem" 
   s.authors   = ["Nick Quaranto"] 
   s.email    = 'nick@quaran.to' 
   s.files    = ["lib/hola.rb", "lib/hola/translator.rb"] 
   s.homepage  = 
    'http://rubygems.org/gems/hola' 
  end 

  % mkdir bin 
  % touch bin/hola 
  % chmod a+x bin/hola 

  #!/usr/bin/env ruby 
   
  require 'hola' 
  puts Hola.hi(ARGV[0]) 

  % ruby -Ilib ./bin/hola 
  hello world 
   
  % ruby -Ilib ./bin/hola spanish 
  hola mundo 

  % head -4 hola.gemspec 
  Gem::Specification.new do |s| 
   s.name    = 'hola' 
   s.version   = '0.0.1' 
   s.executables << 'hola'