important parts of chapter 4 of railstutorial

application.html.erb

# Listing 4.3. The sample application site layout. 
# app/views/layouts/application.html.erb
<title><%= full_title(yield(:title)) %></title>

application_helper.rb

# Listing 4.2. Defining a full_title helper. 
# app/helpers/application_helper.rb
module ApplicationHelper
  # Returns the full title on a per-page basis.
  def full_title(page_title)
    base_title = "Ruby on Rails Tutorial Sample App"
    if page_title.empty?
      base_title
    else
      "#{base_title} | #{page_title}"
    end
  end
end

# Listing 4.4. Updated tests for the Home page’s title. 
# spec/requests/static_pages_spec.rb
(see book)

home.html.erb

# Listing 4.5. The Home page with no custom page title. 
# app/views/static_pages/home.html.erb
<h1>Sample App</h1>
<p>
  This is the home page for the
  <a href="http://railstutorial.org/">Ruby on Rails Tutorial</a>
  sample application.
</p>