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			<h2>Chapters</h2>
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					<a href="#_command_line_basics">Command Line Basics</a>
						<ul>
						
							<li><a href="#_rails">rails</a></li>
						
							<li><a href="#_server">server</a></li>
						
							<li><a href="#_generate">generate</a></li>
						
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		<div id="content">
				<h1>A Guide to The Rails Command Line</h1>
			<div id="preamble">
<div class="sectionbody">
<div class="para"><p>Rails comes with every command line tool you'll need to</p></div>
<div class="ilist"><ul>
<li>
<p>
Create a Rails application
</p>
</li>
<li>
<p>
Generate models, controllers, database migrations, and unit tests
</p>
</li>
<li>
<p>
Start a development server
</p>
</li>
<li>
<p>
Mess with objects through an interactive shell
</p>
</li>
<li>
<p>
Profile and benchmark your new creation
</p>
</li>
</ul></div>
<div class="para"><p>&#8230; and much, much more! (Buy now!)</p></div>
<div class="para"><p>This tutorial assumes you have basic Rails knowledge from reading the Getting Started with Rails Guide.</p></div>
</div>
</div>
<h2 id="_command_line_basics">1. Command Line Basics</h2>
<div class="sectionbody">
<div class="para"><p>There are a few commands that are absolutely critical to your everyday usage of Rails. In the order of how much you'll probably use them are:</p></div>
<div class="ilist"><ul>
<li>
<p>
console
</p>
</li>
<li>
<p>
server
</p>
</li>
<li>
<p>
rake
</p>
</li>
<li>
<p>
generate
</p>
</li>
<li>
<p>
rails
</p>
</li>
</ul></div>
<div class="para"><p>Let's create a simple Rails application to step through each of these commands in context.</p></div>
<h3 id="_rails">1.1. rails</h3>
<div class="para"><p>The first thing we'll want to do is create a new Rails application by running the <tt>rails</tt> command after installing Rails.</p></div>
<div class="admonitionblock">
<table><tr>
<td class="icon">
<img src="./images/icons/note.png" alt="Note" />
</td>
<td class="content">You know you need the rails gem installed by typing <tt>gem install rails</tt> first, right? Okay, okay, just making sure.</td>
</tr></table>
</div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt>$ rails commandsapp

     create
     create  app/controllers
     create  app/helpers
     create  app/models
     <span style="color: #990000">...</span>
     <span style="color: #990000">...</span>
     create  log/production<span style="color: #990000">.</span>log
     create  log/development<span style="color: #990000">.</span>log
     create  log/test<span style="color: #990000">.</span>log
</tt></pre></div></div>
<div class="para"><p>Rails will set you up with what seems like a huge amount of stuff for such a tiny command! You've got the entire Rails directory structure now with all the code you need to run our simple application right out of the box.</p></div>
<div class="admonitionblock">
<table><tr>
<td class="icon">
<img src="./images/icons/note.png" alt="Note" />
</td>
<td class="content">This output will seem very familiar when we get to the <tt>generate</tt> command. Creepy foreshadowing!</td>
</tr></table>
</div>
<h3 id="_server">1.2. server</h3>
<div class="para"><p>Let's try it! The <tt>server</tt> command launches a small web server written in Ruby named WEBrick which was also installed when you installed Rails. You'll use this any time you want to view your work through a web browser.</p></div>
<div class="admonitionblock">
<table><tr>
<td class="icon">
<img src="./images/icons/note.png" alt="Note" />
</td>
<td class="content">WEBrick isn't your only option for serving Rails. We'll get to that in a later section. [XXX: which section]</td>
</tr></table>
</div>
<div class="para"><p>Here we'll flex our <tt>server</tt> command, which without any prodding of any kind will run our new shiny Rails app:</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt>$ cd commandsapp
$ <span style="color: #990000">.</span>/script/server
<span style="color: #990000">=&gt;</span> Booting WEBrick<span style="color: #990000">...</span>
<span style="color: #990000">=&gt;</span> Rails <span style="color: #993399">2.2</span><span style="color: #990000">.</span><span style="color: #993399">0</span> application started on http<span style="color: #990000">://</span><span style="color: #993399">0.0</span><span style="color: #990000">.</span><span style="color: #993399">0.0</span><span style="color: #990000">:</span><span style="color: #993399">3000</span>
<span style="color: #990000">=&gt;</span> Ctrl-C to shutdown server<span style="color: #990000">;</span> call with --help <span style="font-weight: bold"><span style="color: #0000FF">for</span></span> options
<span style="color: #990000">[</span><span style="color: #993399">2008</span>-<span style="color: #993399">11</span>-<span style="color: #993399">04</span> <span style="color: #993399">10</span><span style="color: #990000">:</span><span style="color: #993399">11</span><span style="color: #990000">:</span><span style="color: #993399">38</span><span style="color: #990000">]</span> INFO  WEBrick <span style="color: #993399">1.3</span><span style="color: #990000">.</span><span style="color: #993399">1</span>
<span style="color: #990000">[</span><span style="color: #993399">2008</span>-<span style="color: #993399">11</span>-<span style="color: #993399">04</span> <span style="color: #993399">10</span><span style="color: #990000">:</span><span style="color: #993399">11</span><span style="color: #990000">:</span><span style="color: #993399">38</span><span style="color: #990000">]</span> INFO  ruby <span style="color: #993399">1.8</span><span style="color: #990000">.</span><span style="color: #993399">5</span> <span style="color: #990000">(</span><span style="color: #993399">2006</span>-<span style="color: #993399">12</span>-<span style="color: #993399">04</span><span style="color: #990000">)</span> <span style="color: #990000">[</span>i486-linux<span style="color: #990000">]</span>
<span style="color: #990000">[</span><span style="color: #993399">2008</span>-<span style="color: #993399">11</span>-<span style="color: #993399">04</span> <span style="color: #993399">10</span><span style="color: #990000">:</span><span style="color: #993399">11</span><span style="color: #990000">:</span><span style="color: #993399">38</span><span style="color: #990000">]</span> INFO  WEBrick<span style="color: #990000">::</span>HTTPServer<span style="font-style: italic"><span style="color: #9A1900">#start: pid=18994 port=3000</span></span>
</tt></pre></div></div>
<div class="para"><p>WHOA. With just three commands we whipped up a Rails server listening on port 3000. Go! Go right now to your browser and go to <a href="http://localhost:3000">http://localhost:3000</a>. I'll wait.</p></div>
<div class="para"><p>See? Cool! It doesn't do much yet, but we'll change that.</p></div>
<h3 id="_generate">1.3. generate</h3>
<div class="para"><p>The <tt>generate</tt> command uses templates to create a whole lot of things. You can always find out what's available by running <tt>generate</tt> by itself. Let's do that:</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt>$ <span style="color: #990000">.</span>/script/generate
Usage<span style="color: #990000">:</span> <span style="color: #990000">.</span>/script/generate generator <span style="color: #990000">[</span>options<span style="color: #990000">]</span> <span style="color: #990000">[</span>args<span style="color: #990000">]</span>

<span style="color: #990000">...</span>
<span style="color: #990000">...</span>

Installed Generators
  Builtin<span style="color: #990000">:</span> controller<span style="color: #990000">,</span> integration_test<span style="color: #990000">,</span> mailer<span style="color: #990000">,</span> migration<span style="color: #990000">,</span> model<span style="color: #990000">,</span> observer<span style="color: #990000">,</span> performance_test<span style="color: #990000">,</span> plugin<span style="color: #990000">,</span> resource<span style="color: #990000">,</span> scaffold<span style="color: #990000">,</span> session_migration

<span style="color: #990000">...</span>
<span style="color: #990000">...</span>
</tt></pre></div></div>
<div class="admonitionblock">
<table><tr>
<td class="icon">
<img src="./images/icons/note.png" alt="Note" />
</td>
<td class="content">You can install more generators through generator gems, portions of plugins you'll undoubtedly install, and you can even create your own!</td>
</tr></table>
</div>
<div class="para"><p>Using generators will save you a large amount of time by writing <strong>boilerplate code</strong> for you &#8212; necessary for the darn thing to work, but not necessary for you to spend time writing. That's what we have computers for, right?</p></div>
<div class="para"><p>Let's make our own controller with the controller generator. But what command should we use? Let's ask the generator:</p></div>
<div class="admonitionblock">
<table><tr>
<td class="icon">
<img src="./images/icons/note.png" alt="Note" />
</td>
<td class="content">All Rails console utilities have help text. For commands that require a lot of input to run correctly, you can try the command without any parameters (like <tt>rails</tt> or <tt>./script/generate</tt>). For others, you can try adding <tt>&#8212;help</tt> or <tt>-h</tt> to the end, as in <tt>./script/server &#8212;help</tt>.</td>
</tr></table>
</div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt>$ <span style="color: #990000">.</span>/script/generate controller
Usage<span style="color: #990000">:</span> <span style="color: #990000">.</span>/script/generate controller ControllerName <span style="color: #990000">[</span>options<span style="color: #990000">]</span>

<span style="color: #990000">...</span>
<span style="color: #990000">...</span>

Example<span style="color: #990000">:</span>
    `<span style="color: #990000">.</span>/script/generate controller CreditCard open debit credit close`

    Credit card controller with URLs like /credit_card/debit<span style="color: #990000">.</span>
        Controller<span style="color: #990000">:</span> app/controllers/credit_card_controller<span style="color: #990000">.</span>rb
        Views<span style="color: #990000">:</span>      app/views/credit_card/debit<span style="color: #990000">.</span>html<span style="color: #990000">.</span>erb <span style="color: #990000">[...]</span>
        Helper<span style="color: #990000">:</span>     app/helpers/credit_card_helper<span style="color: #990000">.</span>rb
        Test<span style="color: #990000">:</span>       test/functional/credit_card_controller_test<span style="color: #990000">.</span>rb

Modules Example<span style="color: #990000">:</span>
    `<span style="color: #990000">.</span>/script/generate controller <span style="color: #FF0000">'admin/credit_card'</span> <span style="font-weight: bold"><span style="color: #0000FF">suspend</span></span> late_fee`

    Credit card admin controller with URLs /admin/credit_card/suspend<span style="color: #990000">.</span>
        Controller<span style="color: #990000">:</span> app/controllers/admin/credit_card_controller<span style="color: #990000">.</span>rb
        Views<span style="color: #990000">:</span>      app/views/admin/credit_card/debit<span style="color: #990000">.</span>html<span style="color: #990000">.</span>erb <span style="color: #990000">[...]</span>
        Helper<span style="color: #990000">:</span>     app/helpers/admin/credit_card_helper<span style="color: #990000">.</span>rb
        Test<span style="color: #990000">:</span>       test/functional/admin/credit_card_controller_test<span style="color: #990000">.</span>rb
</tt></pre></div></div>
<div class="para"><p>Ah, the controller generator is expecting parameters in the form of <tt>generate controller ControllerName action1 action2</tt>. Let's make a <tt>Greetings</tt> controller with an action of <strong>hello</strong>, which will say something nice to us.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt>$ <span style="color: #990000">.</span>/script/generate controller Greeting hello
     exists  app/controllers<span style="color: #990000">/</span>
     exists  app/helpers<span style="color: #990000">/</span>
     create  app/views/greeting
     exists  test/functional<span style="color: #990000">/</span>
     create  app/controllers/greetings_controller<span style="color: #990000">.</span>rb
     create  test/functional/greetings_controller_test<span style="color: #990000">.</span>rb
     create  app/helpers/greetings_helper<span style="color: #990000">.</span>rb
     create  app/views/greetings/hello<span style="color: #990000">.</span>html<span style="color: #990000">.</span>erb
</tt></pre></div></div>
<div class="para"><p>Look there! Now what all did this generate? It looks like it made sure a bunch of directories were in our application, and created a controller file, a functional test file, a helper for the view, and a view file.</p></div>
<div class="para"><p>Let's check out the controller and modify it a little (in <tt>app/controllers/greeting_controller.rb</tt>):</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt><span style="font-weight: bold"><span style="color: #0000FF">class</span></span> GreetingController <span style="color: #990000">&lt;</span> ApplicationController
  <span style="font-weight: bold"><span style="color: #0000FF">def</span></span> hello
    <span style="color: #009900">@message</span> <span style="color: #990000">=</span> <span style="color: #FF0000">"Hello, how are you today? I am exuberant!"</span>
  <span style="font-weight: bold"><span style="color: #0000FF">end</span></span>

<span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
</tt></pre></div></div>
<div class="para"><p>Then the view, to display our nice message (in <tt>app/views/greeting/hello.html.erb</tt>):</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt><span style="font-weight: bold"><span style="color: #0000FF">&lt;h1&gt;</span></span>A Greeting for You!<span style="font-weight: bold"><span style="color: #0000FF">&lt;/h1&gt;</span></span>
<span style="font-weight: bold"><span style="color: #0000FF">&lt;p&gt;</span></span>&lt;%= @message %&gt;<span style="font-weight: bold"><span style="color: #0000FF">&lt;/p&gt;</span></span>
</tt></pre></div></div>
<div class="para"><p>Deal. Go check it out in your browser. Fire up your server. Remember? <tt>./script/server</tt> at the root of your Rails application should do it.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt>$ <span style="color: #990000">.</span>/script/server
<span style="color: #990000">=&gt;</span> Booting WEBrick<span style="color: #990000">...</span>
</tt></pre></div></div>
<div class="para"><p>The URL will be <tt>http://localhost:3000/greetings/hello</tt>. I'll wait for you to be suitably impressed.</p></div>
<div class="admonitionblock">
<table><tr>
<td class="icon">
<img src="./images/icons/note.png" alt="Note" />
</td>
<td class="content">With a normal, plain-old Rails application, your URLs will generally follow the pattern of <a href="http://(host)/(controller)/(action">http://(host)/(controller)/(action</a>), and a URL like <a href="http://(host)/(controller">http://(host)/(controller</a>) will hit the <strong>index</strong> action of that controller.</td>
</tr></table>
</div>
<div class="para"><p>"What about data, though?", you ask over a cup of coffee. Rails comes with a generator for data models too. Can you guess its generator name?</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt>$ <span style="color: #990000">.</span>/script/generate model
Usage<span style="color: #990000">:</span> <span style="color: #990000">.</span>/script/generate model ModelName <span style="color: #990000">[</span>field<span style="color: #990000">:</span><span style="font-weight: bold"><span style="color: #0000FF">type</span></span><span style="color: #990000">,</span> field<span style="color: #990000">:</span><span style="font-weight: bold"><span style="color: #0000FF">type</span></span><span style="color: #990000">]</span>

<span style="color: #990000">...</span>

Examples<span style="color: #990000">:</span>
    `<span style="color: #990000">.</span>/script/generate model account`

        creates an Account model<span style="color: #990000">,</span> <span style="font-weight: bold"><span style="color: #0000FF">test</span></span><span style="color: #990000">,</span> fixture<span style="color: #990000">,</span> and migration<span style="color: #990000">:</span>
            Model<span style="color: #990000">:</span>      app/models/account<span style="color: #990000">.</span>rb
            Test<span style="color: #990000">:</span>       test/unit/account_test<span style="color: #990000">.</span>rb
            Fixtures<span style="color: #990000">:</span>   test/fixtures/accounts<span style="color: #990000">.</span>yml
            Migration<span style="color: #990000">:</span>  db/migrate/XXX_add_accounts<span style="color: #990000">.</span>rb

    `<span style="color: #990000">.</span>/script/generate model post title<span style="color: #990000">:</span>string body<span style="color: #990000">:</span>text published<span style="color: #990000">:</span>boolean`

        creates a Post model with a string title<span style="color: #990000">,</span> text body<span style="color: #990000">,</span> and published flag<span style="color: #990000">.</span>
</tt></pre></div></div>
<div class="para"><p>Let's set up a simple model called "HighScore" that will keep track of our highest score on video games we play. Then we'll wire up our controller and view to modify and list our scores.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt>$ <span style="color: #990000">.</span>/script/generate model HighScore id<span style="color: #990000">:</span>integer game<span style="color: #990000">:</span>string score<span style="color: #990000">:</span>integer
      exists  app/models<span style="color: #990000">/</span>
      exists  test/unit<span style="color: #990000">/</span>
      exists  test/fixtures<span style="color: #990000">/</span>
      create  app/models/high_score<span style="color: #990000">.</span>rb
      create  test/unit/high_score_test<span style="color: #990000">.</span>rb
      create  test/fixtures/high_scores<span style="color: #990000">.</span>yml
      create  db/migrate
      create  db/migrate<span style="color: #990000">/</span>20081126032945_create_high_scores<span style="color: #990000">.</span>rb
</tt></pre></div></div>
<div class="para"><p>Taking it from the top, we have the <strong>models</strong> directory, where all of your data models live. <strong>test/unit</strong>, where all the unit tests live (gasp! &#8212; unit tests!), fixtures for those tests, a test, the <strong>migrate</strong> directory, where the database-modifying migrations live, and a migration to create the <tt>high_scores</tt> table with the right fields.</p></div>
<div class="para"><p>The migration requires that we <strong>migrate</strong>, that is, run some Ruby code (living in that <tt>20081126032945_create_high_scores.rb</tt>) to modify the schema of our database. Which database? The sqlite3 database that Rails will create for you when we run the <tt>rake db:migrate</tt> command. We'll talk more about Rake in-depth in a little while.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt>$ rake db<span style="color: #990000">:</span>migrate
<span style="color: #990000">(</span><span style="font-weight: bold"><span style="color: #0000FF">in</span></span> /home/commandsapp<span style="color: #990000">)</span>
<span style="color: #990000">==</span>  CreateHighScores<span style="color: #990000">:</span> migrating <span style="color: #990000">===============================================</span>
-- create_table<span style="color: #990000">(:</span>high_scores<span style="color: #990000">)</span>
   -<span style="color: #990000">&gt;</span> <span style="color: #993399">0</span><span style="color: #990000">.</span>0070s
<span style="color: #990000">==</span>  CreateHighScores<span style="color: #990000">:</span> migrated <span style="color: #990000">(</span><span style="color: #993399">0</span><span style="color: #990000">.</span>0077s<span style="color: #990000">)</span> <span style="color: #990000">======================================</span>
</tt></pre></div></div>
<div class="admonitionblock">
<table><tr>
<td class="icon">
<img src="./images/icons/note.png" alt="Note" />
</td>
<td class="content">Let's talk about unit tests. Unit tests are code that tests and makes assertions about code. In unit testing, we take a little part of code, say a method of a model, and test its inputs and outputs. Unit tests are your friend. The sooner you make peace with the fact that your quality of life will drastically increase when you unit test your code, the better. Seriously. We'll make one in a moment.</td>
</tr></table>
</div>
<div class="para"><p>Yo! Let's shove a small table into our greeting controller and view, listing our sweet scores.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt><span style="font-weight: bold"><span style="color: #0000FF">class</span></span> GreetingController <span style="color: #990000">&lt;</span> ApplicationController
  <span style="font-weight: bold"><span style="color: #0000FF">def</span></span> hello
    <span style="font-weight: bold"><span style="color: #0000FF">if</span></span> request<span style="color: #990000">.</span>post?
      score <span style="color: #990000">=</span> HighScore<span style="color: #990000">.</span>new<span style="color: #990000">(</span>params<span style="color: #990000">[:</span>high_score<span style="color: #990000">])</span>
      <span style="font-weight: bold"><span style="color: #0000FF">if</span></span> score<span style="color: #990000">.</span>save
        flash<span style="color: #990000">[:</span>notice<span style="color: #990000">]</span> <span style="color: #990000">=</span> <span style="color: #FF0000">"New score posted!"</span>
      <span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
    <span style="font-weight: bold"><span style="color: #0000FF">end</span></span>

    <span style="color: #009900">@scores</span> <span style="color: #990000">=</span> HighScore<span style="color: #990000">.</span>find<span style="color: #990000">(:</span>all<span style="color: #990000">)</span>
  <span style="font-weight: bold"><span style="color: #0000FF">end</span></span>

<span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
</tt></pre></div></div>
<div class="para"><p>XXX: Go with scaffolding instead, modifying greeting controller for high scores seems dumb.</p></div>
</div>

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