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<option value="4_0_release_notes.html">Version 4.0 - June 2013</option> <option value="3_2_release_notes.html">Version 3.2 - January 2012</option> <option value="3_1_release_notes.html">Version 3.1 - August 2011</option> <option value="3_0_release_notes.html">Version 3.0 - August 2010</option> <option value="2_3_release_notes.html">Version 2.3 - March 2009</option> <option value="2_2_release_notes.html">Version 2.2 - November 2008</option> </optgroup> </select> </li> </ul> </nav> </div> </header> <hr class="hide" /> <main id="main"> <article> <header id="feature"> <div class="wrapper"> <h1>The Rails Command Line</h1><p>After reading this guide, you will know:</p> <ul> <li>How to create a Rails application.</li> <li>How to generate models, controllers, database migrations, and unit tests.</li> <li>How to start a development server.</li> <li>How to experiment with objects through an interactive shell.</li> </ul> <nav id="column-side" aria-label="Chapter" class="guide-index" data-turbo="false"> <a id="chapter-nav-skip-link" href="#article-body" class="skip-link"> Skip to article body </a> <h2 class="chapter"> <picture aria-hidden="true">  <source srcset="images/icon_book-close-bookmark-1-wht.svg" media="(prefers-color-scheme: dark)" /> <img src="images/icon_book-close-bookmark-1.svg" alt="Chapter Icon" /> </picture> Chapters </h2> <ol class="chapters"> <li><a href="#creating-a-rails-app">Creating a Rails App</a> <ul> <li><a href="#rails-new"><code>rails new</code></a></li> <li><a href="#preconfigure-a-different-database">Preconfigure a Different Database</a></li> </ul></li> <li><a href="#command-line-basics">Command Line Basics</a> <ul> <li><a href="#bin-rails-server"><code>bin/rails server</code></a></li> <li><a href="#bin-rails-generate"><code>bin/rails generate</code></a></li> <li><a href="#bin-rails-console"><code>bin/rails console</code></a></li> <li><a href="#bin-rails-dbconsole"><code>bin/rails dbconsole</code></a></li> <li><a href="#bin-rails-runner"><code>bin/rails runner</code></a></li> <li><a href="#bin-rails-destroy"><code>bin/rails destroy</code></a></li> <li><a href="#bin-rails-about"><code>bin/rails about</code></a></li> <li><a href="#bin-rails-assets"><code>bin/rails assets:</code></a></li> <li><a href="#bin-rails-db"><code>bin/rails db:</code></a></li> <li><a href="#bin-rails-notes"><code>bin/rails notes</code></a></li> <li><a href="#bin-rails-routes"><code>bin/rails routes</code></a></li> <li><a href="#bin-rails-test"><code>bin/rails test</code></a></li> <li><a href="#bin-rails-tmp"><code>bin/rails tmp:</code></a></li> <li><a href="#miscellaneous">Miscellaneous</a></li> <li><a href="#custom-rake-tasks">Custom Rake Tasks</a></li> </ul></li> </ol> </nav> </div> </header> <div class="wrapper"> <div id="column-main"> <section id="article-body"> <div class="interstitial note"><p>This tutorial assumes you have basic Rails knowledge from reading the <a href="getting_started.html">Getting Started with Rails Guide</a>.</p></div><h2 id="creating-a-rails-app"><a class="anchorlink" href="#creating-a-rails-app" data-turbo="false"><span>1</span> Creating a Rails App</a></h2><p>First, let's create a simple Rails application using the <code>rails new</code> command.</p><p>We will use this application to play and discover all the commands described in this guide.</p><div class="interstitial info"><p>You can install the rails gem by typing <code>gem install rails</code>, if you don't have it already.</p></div><h3 id="rails-new"><a class="anchorlink" href="#rails-new" data-turbo="false"><span>1.1</span> <code>rails new</code></a></h3><p>The first argument we'll pass to the <code>rails new</code> command is the application name.</p><div class="interstitial code"> <pre><code class="highlight console"><span class="gp">$</span><span class="w"> </span><span class="nb">rails </span>new my_app <span class="go"> create</span> <span class="go"> create README.md</span> <span class="go"> create Rakefile</span> <span class="go"> create config.ru</span> <span class="go"> create .gitignore</span> <span class="go"> create Gemfile</span> <span class="go"> create app</span> <span class="c"> ...</span> <span class="go"> create tmp/cache</span> <span class="c"> ...</span> <span class="go"> run bundle install</span> </code></pre> <button class="clipboard-button" data-clipboard-text="rails new my_app ">Copy</button> </div> <p>Rails will set up what seems like a huge amount of stuff for such a tiny command! We've got the entire Rails directory structure now with all the code we need to run our simple application right out of the box.</p><p>If you wish to skip some files from being generated or skip some libraries, you can append any of the following arguments to your <code>rails new</code> command:</p> <div class="table-wrapper"><table><thead> <tr> <th>Argument</th> <th>Description</th> </tr> </thead><tbody> <tr> <td><code>--skip-git</code></td> <td>Skip git init, .gitignore, and .gitattributes</td> </tr> <tr> <td><code>--skip-docker</code></td> <td>Skip Dockerfile, .dockerignore and bin/docker-entrypoint</td> </tr> <tr> <td><code>--skip-keeps</code></td> <td>Skip source control .keep files</td> </tr> <tr> <td><code>--skip-action-mailer</code></td> <td>Skip Action Mailer files</td> </tr> <tr> <td><code>--skip-action-mailbox</code></td> <td>Skip Action Mailbox gem</td> </tr> <tr> <td><code>--skip-action-text</code></td> <td>Skip Action Text gem</td> </tr> <tr> <td><code>--skip-active-record</code></td> <td>Skip Active Record files</td> </tr> <tr> <td><code>--skip-active-job</code></td> <td>Skip Active Job</td> </tr> <tr> <td><code>--skip-active-storage</code></td> <td>Skip Active Storage files</td> </tr> <tr> <td><code>--skip-action-cable</code></td> <td>Skip Action Cable files</td> </tr> <tr> <td><code>--skip-asset-pipeline</code></td> <td>Skip Asset Pipeline</td> </tr> <tr> <td><code>--skip-javascript</code></td> <td>Skip JavaScript files</td> </tr> <tr> <td><code>--skip-hotwire</code></td> <td>Skip Hotwire integration</td> </tr> <tr> <td><code>--skip-jbuilder</code></td> <td>Skip jbuilder gem</td> </tr> <tr> <td><code>--skip-test</code></td> <td>Skip test files</td> </tr> <tr> <td><code>--skip-system-test</code></td> <td>Skip system test files</td> </tr> <tr> <td><code>--skip-bootsnap</code></td> <td>Skip bootsnap gem</td> </tr> <tr> <td><code>--skip-dev-gems</code></td> <td>Skip adding development gems</td> </tr> <tr> <td><code>--skip-thruster</code></td> <td>Skip Thruster setup</td> </tr> <tr> <td><code>--skip-rubocop</code></td> <td>Skip RuboCop setup</td> </tr> <tr> <td><code>--skip-brakeman</code></td> <td>Skip brakeman setup</td> </tr> <tr> <td><code>--skip-ci</code></td> <td>Skip GitHub CI files</td> </tr> <tr> <td><code>--skip-kamal</code></td> <td>Skip Kamal setup</td> </tr> <tr> <td><code>--skip-solid</code></td> <td>Skip Solid Cache, Queue, and Cable setup</td> </tr> </tbody></table></div> <p>These are just some of the options that <code>rails new</code> accepts. For a full list of options, type <code>rails new --help</code>.</p><h3 id="preconfigure-a-different-database"><a class="anchorlink" href="#preconfigure-a-different-database" data-turbo="false"><span>1.2</span> Preconfigure a Different Database</a></h3><p>When creating a new Rails application, you have the option to specify what kind of database your application is going to use. This will save you a few minutes, and certainly many keystrokes.</p><p>Let's see what a <code>--database=postgresql</code> option will do for us:</p><div class="interstitial code"> <pre><code class="highlight console"><span class="gp">$</span><span class="w"> </span><span class="nb">rails </span>new petstore <span class="nt">--database</span><span class="o">=</span>postgresql <span class="go"> create</span> <span class="go"> create app/controllers</span> <span class="go"> create app/helpers</span> <span class="c">...</span> </code></pre> <button class="clipboard-button" data-clipboard-text="rails new petstore --database=postgresql ">Copy</button> </div> <p>Let's see what it put in our <code>config/database.yml</code>:</p><div class="interstitial code"> <pre><code class="highlight yaml"><span class="c1"># PostgreSQL. Versions 9.3 and up are supported.</span> <span class="c1">#</span> <span class="c1"># Install the pg driver:</span> <span class="c1"># gem install pg</span> <span class="c1"># On macOS with Homebrew:</span> <span class="c1"># gem install pg -- --with-pg-config=/usr/local/bin/pg_config</span> <span class="c1"># On Windows:</span> <span class="c1"># gem install pg</span> <span class="c1"># Choose the win32 build.</span> <span class="c1"># Install PostgreSQL and put its /bin directory on your path.</span> <span class="c1">#</span> <span class="c1"># Configure Using Gemfile</span> <span class="c1"># gem "pg"</span> <span class="c1">#</span> <span class="na">default</span><span class="pi">:</span> <span class="nl">&default</span> <span class="na">adapter</span><span class="pi">:</span> <span class="s">postgresql</span> <span class="na">encoding</span><span class="pi">:</span> <span class="s">unicode</span> <span class="c1"># For details on connection pooling, see Rails configuration guide</span> <span class="c1"># https://guides.rubyonrails.org/configuring.html#database-pooling</span> <span class="na">pool</span><span class="pi">:</span> <span class="s"><%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %></span> <span class="na">development</span><span class="pi">:</span> <span class="na"><<</span><span class="pi">:</span> <span class="nv">*default</span> <span class="na">database</span><span class="pi">:</span> <span class="s">petstore_development</span> <span class="nn">...</span> </code></pre> <button class="clipboard-button" data-clipboard-text="# PostgreSQL. Versions 9.3 and up are supported. # # Install the pg driver: # gem install pg # On macOS with Homebrew: # gem install pg -- --with-pg-config=/usr/local/bin/pg_config # On Windows: # gem install pg # Choose the win32 build. # Install PostgreSQL and put its /bin directory on your path. # # Configure Using Gemfile # gem "pg" # default: &default adapter: postgresql encoding: unicode # For details on connection pooling, see Rails configuration guide # https://guides.rubyonrails.org/configuring.html#database-pooling pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %> development: <<: *default database: petstore_development ... ">Copy</button> </div> <p>It generated a database configuration corresponding to our choice of PostgreSQL.</p><h2 id="command-line-basics"><a class="anchorlink" href="#command-line-basics" data-turbo="false"><span>2</span> Command Line Basics</a></h2><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> <ul> <li><code>bin/rails console</code></li> <li><code>bin/rails server</code></li> <li><code>bin/rails test</code></li> <li><code>bin/rails generate</code></li> <li><code>bin/rails db:migrate</code></li> <li><code>bin/rails db:create</code></li> <li><code>bin/rails routes</code></li> <li><code>bin/rails dbconsole</code></li> <li><code>rails new app_name</code></li> </ul> <p>You can get a list of rails commands available to you, which will often depend on your current directory, by typing <code>rails --help</code>. Each command has a description, and should help you find the thing you need.</p><div class="interstitial code"> <pre><code class="highlight console"><span class="gp">$</span><span class="w"> </span><span class="nb">rails</span> <span class="nt">--help</span> <span class="go">Usage:</span> <span class="go"> bin/rails COMMAND [options]</span> <span class="go">You must specify a command. The most common commands are:</span> <span class="go"> generate Generate new code (short-cut alias: "g")</span> <span class="go"> console Start the Rails console (short-cut alias: "c")</span> <span class="go"> server Start the Rails server (short-cut alias: "s")</span> <span class="c"> ...</span> <span class="go">All commands can be run with -h (or --help) for more information.</span> <span class="go">In addition to those commands, there are:</span> <span class="go">about List versions of all Rails ...</span> <span class="go">assets:clean[keep] Remove old compiled assets</span> <span class="go">assets:clobber Remove compiled assets</span> <span class="go">assets:environment Load asset compile environment</span> <span class="go">assets:precompile Compile all the assets ...</span> <span class="c">...</span> <span class="go">db:fixtures:load Load fixtures into the ...</span> <span class="go">db:migrate Migrate the database ...</span> <span class="go">db:migrate:status Display status of migrations</span> <span class="go">db:rollback Roll the schema back to ...</span> <span class="go">db:schema:cache:clear Clears a db/schema_cache.yml file</span> <span class="go">db:schema:cache:dump Create a db/schema_cache.yml file</span> <span class="go">db:schema:dump Create a database schema file (either db/schema.rb or db/structure.sql ...</span> <span class="go">db:schema:load Load a database schema file (either db/schema.rb or db/structure.sql ...</span> <span class="go">db:seed Load the seed data ...</span> <span class="go">db:version Retrieve the current schema ...</span> <span class="c">...</span> <span class="go">restart Restart app by touching ...</span> <span class="go">tmp:create Create tmp directories ...</span> </code></pre> <button class="clipboard-button" data-clipboard-text="rails --help ">Copy</button> </div> <h3 id="bin-rails-server"><a class="anchorlink" href="#bin-rails-server" data-turbo="false"><span>2.1</span> <code>bin/rails server</code></a></h3><p>The <code>bin/rails server</code> command launches a web server named Puma which comes bundled with Rails. You'll use this any time you want to access your application through a web browser.</p><p>With no further work, <code>bin/rails server</code> will run our new shiny Rails app:</p><div class="interstitial code"> <pre><code class="highlight console"><span class="gp">$</span><span class="w"> </span><span class="nb">cd </span>my_app <span class="gp">$</span><span class="w"> </span><span class="nb">bin/rails </span>server <span class="gp">=></span><span class="w"> </span>Booting Puma <span class="gp">=></span><span class="w"> </span>Rails 8.0.0 application starting <span class="k">in </span>development <span class="gp">=></span><span class="w"> </span>Run <span class="sb">`</span><span class="nb">bin/rails </span>server <span class="nt">--help</span><span class="sb">`</span> <span class="k">for </span>more startup options <span class="go">Puma starting in single mode...</span> <span class="go">* Puma version: 6.4.0 (ruby 3.1.3-p185) ("The Eagle of Durango")</span> <span class="go">* Min threads: 5</span> <span class="go">* Max threads: 5</span> <span class="go">* Environment: development</span> <span class="go">* PID: 5295</span> <span class="go">* Listening on http://127.0.0.1:3000</span> <span class="go">* Listening on http://[::1]:3000</span> <span class="go">Use Ctrl-C to stop</span> </code></pre> <button class="clipboard-button" data-clipboard-text="cd my_app bin/rails server ">Copy</button> </div> <p>With just three commands we whipped up a Rails server listening on port 3000. Go to your browser and open <a href="http://localhost:3000">http://localhost:3000</a>, you will see a basic Rails app running.</p><div class="interstitial info"><p>You can also use the alias "s" to start the server: <code>bin/rails s</code>.</p></div><p>The server can be run on a different port using the <code>-p</code> option. The default development environment can be changed using <code>-e</code>.</p><div class="interstitial code"> <pre><code class="highlight console"><span class="gp">$</span><span class="w"> </span><span class="nb">bin/rails </span>server <span class="nt">-e</span> production <span class="nt">-p</span> 4000 </code></pre> <button class="clipboard-button" data-clipboard-text="bin/rails server -e production -p 4000 ">Copy</button> </div> <p>The <code>-b</code> option binds Rails to the specified IP, by default it is localhost. You can run a server as a daemon by passing a <code>-d</code> option.</p><h3 id="bin-rails-generate"><a class="anchorlink" href="#bin-rails-generate" data-turbo="false"><span>2.2</span> <code>bin/rails generate</code></a></h3><p>The <code>bin/rails generate</code> command uses templates to create a whole lot of things. Running <code>bin/rails generate</code> by itself gives a list of available generators:</p><div class="interstitial info"><p>You can also use the alias "g" to invoke the generator command: <code>bin/rails g</code>.</p></div><div class="interstitial code"> <pre><code class="highlight console"><span class="gp">$</span><span class="w"> </span><span class="nb">bin/rails </span>generate <span class="go">Usage:</span> <span class="go"> bin/rails generate GENERATOR [args] [options]</span> <span class="c">...</span> <span class="c">...</span> <span class="go">Please choose a generator below.</span> <span class="go">Rails:</span> <span class="go"> assets</span> <span class="go"> channel</span> <span class="go"> controller</span> <span class="go"> generator</span> <span class="c"> ...</span> <span class="c"> ...</span> </code></pre> <button class="clipboard-button" data-clipboard-text="bin/rails generate ">Copy</button> </div> <div class="interstitial note"><p>You can install more generators through generator gems, portions of plugins you'll undoubtedly install, and you can even create your own!</p></div><p>Using generators will save you a large amount of time by writing <strong>boilerplate code</strong>, code that is necessary for the app to work.</p><p>Let's make our own controller with the controller generator. But what command should we use? Let's ask the generator:</p><div class="interstitial info"><p>All Rails console utilities have help text. As with most *nix utilities, you can try adding <code>--help</code> or <code>-h</code> to the end, for example <code>bin/rails server --help</code>.</p></div><div class="interstitial code"> <pre><code class="highlight console"><span class="gp">$</span><span class="w"> </span><span class="nb">bin/rails </span>generate controller <span class="go">Usage:</span> <span class="go"> bin/rails generate controller NAME [action action] [options]</span> <span class="c">...</span> <span class="c">...</span> <span class="go">Description:</span> <span class="c"> ...</span> <span class="go"> To create a controller within a module, specify the controller name as a path like 'parent_module/controller_name'.</span> <span class="c"> ...</span> <span class="go">Example:</span> <span class="go"> `bin/rails generate controller CreditCards open debit credit close`</span> <span class="go"> Credit card controller with URLs like /credit_cards/debit.</span> <span class="go"> Controller: app/controllers/credit_cards_controller.rb</span> <span class="go"> Test: test/controllers/credit_cards_controller_test.rb</span> <span class="go"> Views: app/views/credit_cards/debit.html.erb [...]</span> <span class="go"> Helper: app/helpers/credit_cards_helper.rb</span> </code></pre> <button class="clipboard-button" data-clipboard-text="bin/rails generate controller ">Copy</button> </div> <p>The controller generator is expecting parameters in the form of <code>generate controller ControllerName action1 action2</code>. Let's make a <code>Greetings</code> controller with an action of <strong>hello</strong>, which will say something nice to us.</p><div class="interstitial code"> <pre><code class="highlight console"><span class="gp">$</span><span class="w"> </span><span class="nb">bin/rails </span>generate controller Greetings hello <span class="go"> create app/controllers/greetings_controller.rb</span> <span class="go"> route get 'greetings/hello'</span> <span class="go"> invoke erb</span> <span class="go"> create app/views/greetings</span> <span class="go"> create app/views/greetings/hello.html.erb</span> <span class="go"> invoke test_unit</span> <span class="go"> create test/controllers/greetings_controller_test.rb</span> <span class="go"> invoke helper</span> <span class="go"> create app/helpers/greetings_helper.rb</span> <span class="go"> invoke test_unit</span> </code></pre> <button class="clipboard-button" data-clipboard-text="bin/rails generate controller Greetings hello ">Copy</button> </div> <p>What did all this generate? It made sure a bunch of directories were in our application, and created a controller file, a view file, a functional test file, a helper for the view, a JavaScript file, and a stylesheet file.</p><p>Check out the controller and modify it a little (in <code>app/controllers/greetings_controller.rb</code>):</p><div class="interstitial code"> <pre><code class="highlight ruby"><span class="k">class</span> <span class="nc">GreetingsController</span> <span class="o"><</span> <span class="no">ApplicationController</span> <span class="k">def</span> <span class="nf">hello</span> <span class="vi">@message</span> <span class="o">=</span> <span class="s2">"Hello, how are you today?"</span> <span class="k">end</span> <span class="k">end</span> </code></pre> <button class="clipboard-button" data-clipboard-text="class GreetingsController < ApplicationController def hello @message = "Hello, how are you today?" end end ">Copy</button> </div> <p>Then the view, to display our message (in <code>app/views/greetings/hello.html.erb</code>):</p><div class="interstitial code"> <pre><code class="highlight erb"><span class="nt"><h1></span>A Greeting for You!<span class="nt"></h1></span> <span class="nt"><p></span><span class="cp"><%=</span> <span class="vi">@message</span> <span class="cp">%></span><span class="nt"></p></span> </code></pre> <button class="clipboard-button" data-clipboard-text="<h1>A Greeting for You!</h1> <p><%= @message %></p> ">Copy</button> </div> <p>Fire up your server using <code>bin/rails server</code>.</p><div class="interstitial code"> <pre><code class="highlight console"><span class="gp">$</span><span class="w"> </span><span class="nb">bin/rails </span>server <span class="gp">=></span><span class="w"> </span>Booting Puma... </code></pre> <button class="clipboard-button" data-clipboard-text="bin/rails server ">Copy</button> </div> <p>The URL will be <a href="http://localhost:3000/greetings/hello">http://localhost:3000/greetings/hello</a>.</p><div class="interstitial info"><p>With a normal, plain-old Rails application, your URLs will generally follow the pattern of http://(host)/(controller)/(action), and a URL like http://(host)/(controller) will hit the <strong>index</strong> action of that controller.</p></div><p>Rails comes with a generator for data models too.</p><div class="interstitial code"> <pre><code class="highlight console"><span class="gp">$</span><span class="w"> </span><span class="nb">bin/rails </span>generate model <span class="go">Usage:</span> <span class="go"> bin/rails generate model NAME [field[:type][:index] field[:type][:index]] [options]</span> <span class="c">...</span> <span class="go">ActiveRecord options:</span> <span class="gp"> [--migration], [--no-migration] #</span><span class="w"> </span>Indicates when to generate migration <span class="gp"> #</span><span class="w"> </span>Default: <span class="nb">true</span> <span class="c">...</span> <span class="go">Description:</span> <span class="go"> Generates a new model. Pass the model name, either CamelCased or</span> <span class="go"> under_scored, and an optional list of attribute pairs as arguments.</span> <span class="c">...</span> </code></pre> <button class="clipboard-button" data-clipboard-text="bin/rails generate model ">Copy</button> </div> <div class="interstitial note"><p>For a list of available field types for the <code>type</code> parameter, refer to the <a href="https://api.rubyonrails.org/v8.0.1/classes/ActiveRecord/ConnectionAdapters/SchemaStatements.html#method-i-add_column">API documentation</a> for the add_column method for the <code>SchemaStatements</code> module. The <code>index</code> parameter generates a corresponding index for the column.</p></div><p>But instead of generating a model directly (which we'll be doing later), let's set up a scaffold. A <strong>scaffold</strong> in Rails is a full set of model, database migration for that model, controller to manipulate it, views to view and manipulate the data, and a test suite for each of the above.</p><p>We will set up a simple resource called "HighScore" that will keep track of our highest score on video games we play.</p><div class="interstitial code"> <pre><code class="highlight console"><span class="gp">$</span><span class="w"> </span><span class="nb">bin/rails </span>generate scaffold HighScore game:string score:integer <span class="go"> invoke active_record</span> <span class="go"> create db/migrate/20190416145729_create_high_scores.rb</span> <span class="go"> create app/models/high_score.rb</span> <span class="go"> invoke test_unit</span> <span class="go"> create test/models/high_score_test.rb</span> <span class="go"> create test/fixtures/high_scores.yml</span> <span class="go"> invoke resource_route</span> <span class="go"> route resources :high_scores</span> <span class="go"> invoke scaffold_controller</span> <span class="go"> create app/controllers/high_scores_controller.rb</span> <span class="go"> invoke erb</span> <span class="go"> create app/views/high_scores</span> <span class="go"> create app/views/high_scores/index.html.erb</span> <span class="go"> create app/views/high_scores/edit.html.erb</span> <span class="go"> create app/views/high_scores/show.html.erb</span> <span class="go"> create app/views/high_scores/new.html.erb</span> <span class="go"> create app/views/high_scores/_form.html.erb</span> <span class="go"> invoke test_unit</span> <span class="go"> create test/controllers/high_scores_controller_test.rb</span> <span class="go"> create test/system/high_scores_test.rb</span> <span class="go"> invoke helper</span> <span class="go"> create app/helpers/high_scores_helper.rb</span> <span class="go"> invoke test_unit</span> <span class="go"> invoke jbuilder</span> <span class="go"> create app/views/high_scores/index.json.jbuilder</span> <span class="go"> create app/views/high_scores/show.json.jbuilder</span> <span class="go"> create app/views/high_scores/_high_score.json.jbuilder</span> </code></pre> <button class="clipboard-button" data-clipboard-text="bin/rails generate scaffold HighScore game:string score:integer ">Copy</button> </div> <p>The generator creates the model, views, controller, <strong>resource</strong> route, and database migration (which creates the <code>high_scores</code> table) for HighScore. And it adds tests for those.</p><p>The migration requires that we <strong>migrate</strong>, that is, run some Ruby code (the <code>20190416145729_create_high_scores.rb</code> file from the above output) to modify the schema of our database. Which database? The SQLite3 database that Rails will create for you when we run the <code>bin/rails db:migrate</code> command. We'll talk more about that command below.</p><div class="interstitial code"> <pre><code class="highlight console"><span class="gp">$</span><span class="w"> </span><span class="nb">bin/rails </span>db:migrate <span class="go">== CreateHighScores: migrating ===============================================</span> <span class="go">-- create_table(:high_scores)</span> <span class="gp"> -></span><span class="w"> </span>0.0017s <span class="go">== CreateHighScores: migrated (0.0019s) ======================================</span> </code></pre> <button class="clipboard-button" data-clipboard-text="bin/rails db:migrate ">Copy</button> </div> <div class="interstitial info"><p>Let's talk about unit tests. Unit tests are code that tests and makes assertions about code. In unit testing, we take a little part of code, say a method of a model, and test its inputs and outputs. Unit tests are your friend. The sooner you make peace with the fact that your quality of life will drastically increase when you unit test your code, the better. Seriously. Please visit <a href="testing.html">the testing guide</a> for an in-depth look at unit testing.</p></div><p>Let's see the interface Rails created for us.</p><div class="interstitial code"> <pre><code class="highlight console"><span class="gp">$</span><span class="w"> </span><span class="nb">bin/rails </span>server </code></pre> <button class="clipboard-button" data-clipboard-text="bin/rails server ">Copy</button> </div> <p>Go to your browser and open <a href="http://localhost:3000/high_scores">http://localhost:3000/high_scores</a>, now we can create new high scores (55,160 on Space Invaders!)</p><h3 id="bin-rails-console"><a class="anchorlink" href="#bin-rails-console" data-turbo="false"><span>2.3</span> <code>bin/rails console</code></a></h3><p>The <code>console</code> command lets you interact with your Rails application from the command line. On the underside, <code>bin/rails console</code> uses IRB, so if you've ever used it, you'll be right at home. This is useful for testing out quick ideas with code and changing data server-side without touching the website.</p><div class="interstitial info"><p>You can also use the alias "c" to invoke the console: <code>bin/rails c</code>.</p></div><p>You can specify the environment in which the <code>console</code> command should operate.</p><div class="interstitial code"> <pre><code class="highlight console"><span class="gp">$</span><span class="w"> </span><span class="nb">bin/rails </span>console <span class="nt">-e</span> staging </code></pre> <button class="clipboard-button" data-clipboard-text="bin/rails console -e staging ">Copy</button> </div> <p>If you wish to test out some code without changing any data, you can do that by invoking <code>bin/rails console --sandbox</code>.</p><div class="interstitial code"> <pre><code class="highlight console"><span class="gp">$</span><span class="w"> </span><span class="nb">bin/rails </span>console <span class="nt">--sandbox</span> <span class="go">Loading development environment in sandbox (Rails 8.0.0)</span> <span class="go">Any modifications you make will be rolled back on exit</span> <span class="gp">irb(main):001:0></span> </code></pre> <button class="clipboard-button" data-clipboard-text="bin/rails console --sandbox ">Copy</button> </div> <h4 id="the-app-and-helper-objects"><a class="anchorlink" href="#the-app-and-helper-objects" data-turbo="false"><span>2.3.1</span> The <code>app</code> and <code>helper</code> Objects</a></h4><p>Inside the <code>bin/rails console</code> you have access to the <code>app</code> and <code>helper</code> instances.</p><p>With the <code>app</code> method you can access named route helpers, as well as do requests.</p><div class="interstitial code"> <pre><code class="highlight irb"><span class="gp">irb></span><span class="w"> </span><span class="n">app</span><span class="p">.</span><span class="nf">root_path</span> <span class="p">=></span> <span class="s2">"/"</span> <span class="gp">irb></span><span class="w"> </span><span class="n">app</span><span class="p">.</span><span class="nf">get</span> <span class="n">_</span> <span class="go">Started GET "/" for 127.0.0.1 at 2014-06-19 10:41:57 -0300</span> <span class="c">...</span> </code></pre> <button class="clipboard-button" data-clipboard-text="app.root_path app.get _ ">Copy</button> </div> <p>With the <code>helper</code> method it is possible to access Rails and your application's helpers.</p><div class="interstitial code"> <pre><code class="highlight irb"><span class="gp">irb></span><span class="w"> </span><span class="n">helper</span><span class="p">.</span><span class="nf">time_ago_in_words</span> <span class="mi">30</span><span class="p">.</span><span class="nf">days</span><span class="p">.</span><span class="nf">ago</span> <span class="p">=></span> <span class="s2">"about 1 month"</span> <span class="gp">irb></span><span class="w"> </span><span class="n">helper</span><span class="p">.</span><span class="nf">my_custom_helper</span> <span class="p">=></span> <span class="s2">"my custom helper"</span> </code></pre> <button class="clipboard-button" data-clipboard-text="helper.time_ago_in_words 30.days.ago helper.my_custom_helper ">Copy</button> </div> <h3 id="bin-rails-dbconsole"><a class="anchorlink" href="#bin-rails-dbconsole" data-turbo="false"><span>2.4</span> <code>bin/rails dbconsole</code></a></h3><p><code>bin/rails dbconsole</code> figures out which database you're using and drops you into whichever command line interface you would use with it (and figures out the command line parameters to give to it, too!). It supports MySQL (including MariaDB), PostgreSQL, and SQLite3.</p><div class="interstitial info"><p>You can also use the alias "db" to invoke the dbconsole: <code>bin/rails db</code>.</p></div><p>If you are using multiple databases, <code>bin/rails dbconsole</code> will connect to the primary database by default. You can specify which database to connect to using <code>--database</code> or <code>--db</code>:</p><div class="interstitial code"> <pre><code class="highlight console"><span class="gp">$</span><span class="w"> </span><span class="nb">bin/rails </span>dbconsole <span class="nt">--database</span><span class="o">=</span>animals </code></pre> <button class="clipboard-button" data-clipboard-text="bin/rails dbconsole --database=animals ">Copy</button> </div> <h3 id="bin-rails-runner"><a class="anchorlink" href="#bin-rails-runner" data-turbo="false"><span>2.5</span> <code>bin/rails runner</code></a></h3><p><code>runner</code> runs Ruby code in the context of the Rails application non-interactively, without having to open Rails <code>console</code>. For instance:</p><div class="interstitial code"> <pre><code class="highlight console"><span class="gp">$</span><span class="w"> </span><span class="nb">bin/rails </span>runner <span class="s2">"Model.long_running_method"</span> </code></pre> <button class="clipboard-button" data-clipboard-text="bin/rails runner "Model.long_running_method" ">Copy</button> </div> <div class="interstitial info"><p>You can also use the alias "r" to invoke the runner: <code>bin/rails r</code>.</p></div><p>You can specify the environment in which the <code>runner</code> command should operate using the <code>-e</code> switch.</p><div class="interstitial code"> <pre><code class="highlight console"><span class="gp">$</span><span class="w"> </span><span class="nb">bin/rails </span>runner <span class="nt">-e</span> staging <span class="s2">"Model.long_running_method"</span> </code></pre> <button class="clipboard-button" data-clipboard-text="bin/rails runner -e staging "Model.long_running_method" ">Copy</button> </div> <p>You can even execute ruby code written in a file with runner.</p><div class="interstitial code"> <pre><code class="highlight console"><span class="gp">$</span><span class="w"> </span><span class="nb">bin/rails </span>runner lib/code_to_be_run.rb </code></pre> <button class="clipboard-button" data-clipboard-text="bin/rails runner lib/code_to_be_run.rb ">Copy</button> </div> <p>By default, <code>rails runner</code> scripts are automatically wrapped with the Rails Executor, which helps report uncaught exceptions for tasks like cron jobs.</p><p>Therefore, executing <code>rails runner lib/long_running_scripts.rb</code> is functionally equivalent to the following:</p><div class="interstitial code"> <pre><code class="highlight ruby"><span class="no">Rails</span><span class="p">.</span><span class="nf">application</span><span class="p">.</span><span class="nf">executor</span><span class="p">.</span><span class="nf">wrap</span> <span class="k">do</span> <span class="c1"># executes code inside lib/long_running_scripts.rb</span> <span class="k">end</span> </code></pre> <button class="clipboard-button" data-clipboard-text="Rails.application.executor.wrap do # executes code inside lib/long_running_scripts.rb end ">Copy</button> </div> <p>You can opt out of this behaviour by using the <code>--skip-executor</code> option.</p><div class="interstitial code"> <pre><code class="highlight console"><span class="gp">$</span><span class="w"> </span><span class="nb">bin/rails </span>runner <span class="nt">--skip-executor</span> lib/long_running_script.rb </code></pre> <button class="clipboard-button" data-clipboard-text="bin/rails runner --skip-executor lib/long_running_script.rb ">Copy</button> </div> <h3 id="bin-rails-destroy"><a class="anchorlink" href="#bin-rails-destroy" data-turbo="false"><span>2.6</span> <code>bin/rails destroy</code></a></h3><p>Think of <code>destroy</code> as the opposite of <code>generate</code>. It'll figure out what generate did, and undo it.</p><div class="interstitial info"><p>You can also use the alias "d" to invoke the destroy command: <code>bin/rails d</code>.</p></div><div class="interstitial code"> <pre><code class="highlight console"><span class="gp">$</span><span class="w"> </span><span class="nb">bin/rails </span>generate model Oops <span class="go"> invoke active_record</span> <span class="go"> create db/migrate/20120528062523_create_oops.rb</span> <span class="go"> create app/models/oops.rb</span> <span class="go"> invoke test_unit</span> <span class="go"> create test/models/oops_test.rb</span> <span class="go"> create test/fixtures/oops.yml</span> </code></pre> <button class="clipboard-button" data-clipboard-text="bin/rails generate model Oops ">Copy</button> </div> <div class="interstitial code"> <pre><code class="highlight console"><span class="gp">$</span><span class="w"> </span><span class="nb">bin/rails </span>destroy model Oops <span class="go"> invoke active_record</span> <span class="go"> remove db/migrate/20120528062523_create_oops.rb</span> <span class="go"> remove app/models/oops.rb</span> <span class="go"> invoke test_unit</span> <span class="go"> remove test/models/oops_test.rb</span> <span class="go"> remove test/fixtures/oops.yml</span> </code></pre> <button class="clipboard-button" data-clipboard-text="bin/rails destroy model Oops ">Copy</button> </div> <h3 id="bin-rails-about"><a class="anchorlink" href="#bin-rails-about" data-turbo="false"><span>2.7</span> <code>bin/rails about</code></a></h3><p><code>bin/rails about</code> gives information about version numbers for Ruby, RubyGems, Rails, the Rails subcomponents, your application's folder, the current Rails environment name, your app's database adapter, and schema version. It is useful when you need to ask for help, check if a security patch might affect you, or when you need some stats for an existing Rails installation.</p><div class="interstitial code"> <pre><code class="highlight console"><span class="gp">$</span><span class="w"> </span><span class="nb">bin/rails </span>about <span class="go">About your application's environment</span> <span class="go">Rails version 8.0.0</span> <span class="go">Ruby version 3.2.0 (x86_64-linux)</span> <span class="go">RubyGems version 3.3.7</span> <span class="go">Rack version 3.0.8</span> <span class="go">JavaScript Runtime Node.js (V8)</span> <span class="go">Middleware: ActionDispatch::HostAuthorization, Rack::Sendfile, ActionDispatch::Static, ActionDispatch::Executor, ActionDispatch::ServerTiming, ActiveSupport::Cache::Strategy::LocalCache::Middleware, Rack::Runtime, Rack::MethodOverride, ActionDispatch::RequestId, ActionDispatch::RemoteIp, Sprockets::Rails::QuietAssets, Rails::Rack::Logger, ActionDispatch::ShowExceptions, WebConsole::Middleware, ActionDispatch::DebugExceptions, ActionDispatch::ActionableExceptions, ActionDispatch::Reloader, ActionDispatch::Callbacks, ActiveRecord::Migration::CheckPending, ActionDispatch::Cookies, ActionDispatch::Session::CookieStore, ActionDispatch::Flash, ActionDispatch::ContentSecurityPolicy::Middleware, ActionDispatch::PermissionsPolicy::Middleware, Rack::Head, Rack::ConditionalGet, Rack::ETag, Rack::TempfileReaper</span> <span class="go">Application root /home/foobar/my_app</span> <span class="go">Environment development</span> <span class="go">Database adapter sqlite3</span> <span class="go">Database schema version 20180205173523</span> </code></pre> <button class="clipboard-button" data-clipboard-text="bin/rails about ">Copy</button> </div> <h3 id="bin-rails-assets"><a class="anchorlink" href="#bin-rails-assets" data-turbo="false"><span>2.8</span> <code>bin/rails assets:</code></a></h3><p>You can precompile the assets in <code>app/assets</code> using <code>bin/rails assets:precompile</code>, and remove older compiled assets using <code>bin/rails assets:clean</code>. The <code>assets:clean</code> command allows for rolling deploys that may still be linking to an old asset while the new assets are being built.</p><p>If you want to clear <code>public/assets</code> completely, you can use <code>bin/rails assets:clobber</code>.</p><h3 id="bin-rails-db"><a class="anchorlink" href="#bin-rails-db" data-turbo="false"><span>2.9</span> <code>bin/rails db:</code></a></h3><p>The most common commands of the <code>db:</code> rails namespace are <code>migrate</code> and <code>create</code>, and it will pay off to try out all of the migration rails commands (<code>up</code>, <code>down</code>, <code>redo</code>, <code>reset</code>). <code>bin/rails db:version</code> is useful when troubleshooting, telling you the current version of the database.</p><p>More information about migrations can be found in the <a href="active_record_migrations.html">Migrations</a> guide.</p><h3 id="bin-rails-notes"><a class="anchorlink" href="#bin-rails-notes" data-turbo="false"><span>2.10</span> <code>bin/rails notes</code></a></h3><p><code>bin/rails notes</code> searches through your code for comments beginning with a specific keyword. You can refer to <code>bin/rails notes --help</code> for information about usage.</p><p>By default, it will search in <code>app</code>, <code>config</code>, <code>db</code>, <code>lib</code>, and <code>test</code> directories for FIXME, OPTIMIZE, and TODO annotations in files with extension <code>.builder</code>, <code>.rb</code>, <code>.rake</code>, <code>.yml</code>, <code>.yaml</code>, <code>.ruby</code>, <code>.css</code>, <code>.js</code>, and <code>.erb</code>.</p><div class="interstitial code"> <pre><code class="highlight console"><span class="gp">$</span><span class="w"> </span><span class="nb">bin/rails </span>notes <span class="go">app/controllers/admin/users_controller.rb:</span> <span class="go"> * [ 20] [TODO] any other way to do this?</span> <span class="go"> * [132] [FIXME] high priority for next deploy</span> <span class="go">lib/school.rb:</span> <span class="go"> * [ 13] [OPTIMIZE] refactor this code to make it faster</span> <span class="go"> * [ 17] [FIXME]</span> </code></pre> <button class="clipboard-button" data-clipboard-text="bin/rails notes ">Copy</button> </div> <h4 id="annotations"><a class="anchorlink" href="#annotations" data-turbo="false"><span>2.10.1</span> Annotations</a></h4><p>You can pass specific annotations by using the <code>--annotations</code> argument. By default, it will search for FIXME, OPTIMIZE, and TODO. Note that annotations are case sensitive.</p><div class="interstitial code"> <pre><code class="highlight console"><span class="gp">$</span><span class="w"> </span><span class="nb">bin/rails </span>notes <span class="nt">--annotations</span> FIXME RELEASE <span class="go">app/controllers/admin/users_controller.rb:</span> <span class="go"> * [101] [RELEASE] We need to look at this before next release</span> <span class="go"> * [132] [FIXME] high priority for next deploy</span> <span class="go">lib/school.rb:</span> <span class="go"> * [ 17] [FIXME]</span> </code></pre> <button class="clipboard-button" data-clipboard-text="bin/rails notes --annotations FIXME RELEASE ">Copy</button> </div> <h4 id="tags"><a class="anchorlink" href="#tags" data-turbo="false"><span>2.10.2</span> Tags</a></h4><p>You can add more default tags to search for by using <code>config.annotations.register_tags</code>. It receives a list of tags.</p><div class="interstitial code"> <pre><code class="highlight ruby"><span class="n">config</span><span class="p">.</span><span class="nf">annotations</span><span class="p">.</span><span class="nf">register_tags</span><span class="p">(</span><span class="s2">"DEPRECATEME"</span><span class="p">,</span> <span class="s2">"TESTME"</span><span class="p">)</span> </code></pre> <button class="clipboard-button" data-clipboard-text="config.annotations.register_tags("DEPRECATEME", "TESTME") ">Copy</button> </div> <div class="interstitial code"> <pre><code class="highlight console"><span class="gp">$</span><span class="w"> </span><span class="nb">bin/rails </span>notes <span class="go">app/controllers/admin/users_controller.rb:</span> <span class="go"> * [ 20] [TODO] do A/B testing on this</span> <span class="go"> * [ 42] [TESTME] this needs more functional tests</span> <span class="go"> * [132] [DEPRECATEME] ensure this method is deprecated in next release</span> </code></pre> <button class="clipboard-button" data-clipboard-text="bin/rails notes ">Copy</button> </div> <h4 id="directories"><a class="anchorlink" href="#directories" data-turbo="false"><span>2.10.3</span> Directories</a></h4><p>You can add more default directories to search from by using <code>config.annotations.register_directories</code>. It receives a list of directory names.</p><div class="interstitial code"> <pre><code class="highlight ruby"><span class="n">config</span><span class="p">.</span><span class="nf">annotations</span><span class="p">.</span><span class="nf">register_directories</span><span class="p">(</span><span class="s2">"spec"</span><span class="p">,</span> <span class="s2">"vendor"</span><span class="p">)</span> </code></pre> <button class="clipboard-button" data-clipboard-text="config.annotations.register_directories("spec", "vendor") ">Copy</button> </div> <div class="interstitial code"> <pre><code class="highlight console"><span class="gp">$</span><span class="w"> </span><span class="nb">bin/rails </span>notes <span class="go">app/controllers/admin/users_controller.rb:</span> <span class="go"> * [ 20] [TODO] any other way to do this?</span> <span class="go"> * [132] [FIXME] high priority for next deploy</span> <span class="go">lib/school.rb:</span> <span class="go"> * [ 13] [OPTIMIZE] Refactor this code to make it faster</span> <span class="go"> * [ 17] [FIXME]</span> <span class="go">spec/models/user_spec.rb:</span> <span class="go"> * [122] [TODO] Verify the user that has a subscription works</span> <span class="go">vendor/tools.rb:</span> <span class="go"> * [ 56] [TODO] Get rid of this dependency</span> </code></pre> <button class="clipboard-button" data-clipboard-text="bin/rails notes ">Copy</button> </div> <h4 id="extensions"><a class="anchorlink" href="#extensions" data-turbo="false"><span>2.10.4</span> Extensions</a></h4><p>You can add more default file extensions to search from by using <code>config.annotations.register_extensions</code>. It receives a list of extensions with its corresponding regex to match it up.</p><div class="interstitial code"> <pre><code class="highlight ruby"><span class="n">config</span><span class="p">.</span><span class="nf">annotations</span><span class="p">.</span><span class="nf">register_extensions</span><span class="p">(</span><span class="s2">"scss"</span><span class="p">,</span> <span class="s2">"sass"</span><span class="p">)</span> <span class="p">{</span> <span class="o">|</span><span class="n">annotation</span><span class="o">|</span> <span class="sr">/\/\/\s*(</span><span class="si">#{</span><span class="n">annotation</span><span class="si">}</span><span class="sr">):?\s*(.*)$/</span> <span class="p">}</span> </code></pre> <button class="clipboard-button" data-clipboard-text="config.annotations.register_extensions("scss", "sass") { |annotation| /\/\/\s*(#{annotation}):?\s*(.*)$/ } ">Copy</button> </div> <div class="interstitial code"> <pre><code class="highlight console"><span class="gp">$</span><span class="w"> </span><span class="nb">bin/rails </span>notes <span class="go">app/controllers/admin/users_controller.rb:</span> <span class="go"> * [ 20] [TODO] any other way to do this?</span> <span class="go"> * [132] [FIXME] high priority for next deploy</span> <span class="go">app/assets/stylesheets/application.css.sass:</span> <span class="go"> * [ 34] [TODO] Use pseudo element for this class</span> <span class="go">app/assets/stylesheets/application.css.scss:</span> <span class="go"> * [ 1] [TODO] Split into multiple components</span> <span class="go">lib/school.rb:</span> <span class="go"> * [ 13] [OPTIMIZE] Refactor this code to make it faster</span> <span class="go"> * [ 17] [FIXME]</span> <span class="go">spec/models/user_spec.rb:</span> <span class="go"> * [122] [TODO] Verify the user that has a subscription works</span> <span class="go">vendor/tools.rb:</span> <span class="go"> * [ 56] [TODO] Get rid of this dependency</span> </code></pre> <button class="clipboard-button" data-clipboard-text="bin/rails notes ">Copy</button> </div> <h3 id="bin-rails-routes"><a class="anchorlink" href="#bin-rails-routes" data-turbo="false"><span>2.11</span> <code>bin/rails routes</code></a></h3><p><code>bin/rails routes</code> will list all of your defined routes, which is useful for tracking down routing problems in your app, or giving you a good overview of the URLs in an app you're trying to get familiar with.</p><h3 id="bin-rails-test"><a class="anchorlink" href="#bin-rails-test" data-turbo="false"><span>2.12</span> <code>bin/rails test</code></a></h3><div class="interstitial info"><p>A good description of unit testing in Rails is given in <a href="testing.html">A Guide to Testing Rails Applications</a></p></div><p>Rails comes with a test framework called minitest. Rails owes its stability to the use of tests. The commands available in the <code>test:</code> namespace helps in running the different tests you will hopefully write.</p><h3 id="bin-rails-tmp"><a class="anchorlink" href="#bin-rails-tmp" data-turbo="false"><span>2.13</span> <code>bin/rails tmp:</code></a></h3><p>The <code>Rails.root/tmp</code> directory is, like the *nix /tmp directory, the holding place for temporary files like process id files and cached actions.</p><p>The <code>tmp:</code> namespaced commands will help you clear and create the <code>Rails.root/tmp</code> directory:</p> <ul> <li><code>bin/rails tmp:cache:clear</code> clears <code>tmp/cache</code>.</li> <li><code>bin/rails tmp:sockets:clear</code> clears <code>tmp/sockets</code>.</li> <li><code>bin/rails tmp:screenshots:clear</code> clears <code>tmp/screenshots</code>.</li> <li><code>bin/rails tmp:clear</code> clears all cache, sockets, and screenshot files.</li> <li><code>bin/rails tmp:create</code> creates tmp directories for cache, sockets, and pids.</li> </ul> <h3 id="miscellaneous"><a class="anchorlink" href="#miscellaneous" data-turbo="false"><span>2.14</span> Miscellaneous</a></h3> <ul> <li><code>bin/rails initializers</code> prints out all defined initializers in the order they are invoked by Rails.</li> <li><code>bin/rails middleware</code> lists Rack middleware stack enabled for your app.</li> <li><code>bin/rails stats</code> is great for looking at statistics on your code, displaying things like KLOCs (thousands of lines of code) and your code to test ratio.</li> <li><code>bin/rails secret</code> will give you a pseudo-random key to use for your session secret.</li> <li><code>bin/rails time:zones:all</code> lists all the timezones Rails knows about.</li> <li><code>bin/rails boot</code> boots the application and exits.</li> </ul> <h3 id="custom-rake-tasks"><a class="anchorlink" href="#custom-rake-tasks" data-turbo="false"><span>2.15</span> Custom Rake Tasks</a></h3><p>Custom rake tasks have a <code>.rake</code> extension and are placed in <code>Rails.root/lib/tasks</code>. You can create these custom rake tasks with the <code>bin/rails generate task</code> command.</p><div class="interstitial code"> <pre><code class="highlight ruby"><span class="n">desc</span> <span class="s2">"I am short, but comprehensive description for my cool task"</span> <span class="n">task</span> <span class="ss">task_name: </span><span class="p">[</span><span class="ss">:prerequisite_task</span><span class="p">,</span> <span class="ss">:another_task_we_depend_on</span><span class="p">]</span> <span class="k">do</span> <span class="c1"># All your magic here</span> <span class="c1"># Any valid Ruby code is allowed</span> <span class="k">end</span> </code></pre> <button class="clipboard-button" data-clipboard-text="desc "I am short, but comprehensive description for my cool task" task task_name: [:prerequisite_task, :another_task_we_depend_on] do # All your magic here # Any valid Ruby code is allowed end ">Copy</button> </div> <p>To pass arguments to your custom rake task:</p><div class="interstitial code"> <pre><code class="highlight ruby"><span class="n">task</span> <span class="ss">:task_name</span><span class="p">,</span> <span class="p">[</span><span class="ss">:arg_1</span><span class="p">]</span> <span class="o">=></span> <span class="p">[</span><span class="ss">:prerequisite_1</span><span class="p">,</span> <span class="ss">:prerequisite_2</span><span class="p">]</span> <span class="k">do</span> <span class="o">|</span><span class="n">task</span><span class="p">,</span> <span class="n">args</span><span class="o">|</span> <span class="n">argument_1</span> <span class="o">=</span> <span class="n">args</span><span class="p">.</span><span class="nf">arg_1</span> <span class="k">end</span> </code></pre> <button class="clipboard-button" data-clipboard-text="task :task_name, [:arg_1] => [:prerequisite_1, :prerequisite_2] do |task, args| argument_1 = args.arg_1 end ">Copy</button> </div> <p>You can group tasks by placing them in namespaces:</p><div class="interstitial code"> <pre><code class="highlight ruby"><span class="n">namespace</span> <span class="ss">:db</span> <span class="k">do</span> <span class="n">desc</span> <span class="s2">"This task does nothing"</span> <span class="n">task</span> <span class="ss">:nothing</span> <span class="k">do</span> <span class="c1"># Seriously, nothing</span> <span class="k">end</span> <span class="k">end</span> </code></pre> <button class="clipboard-button" data-clipboard-text="namespace :db do desc "This task does nothing" task :nothing do # Seriously, nothing end end ">Copy</button> </div> <p>Invocation of the tasks will look like:</p><div class="interstitial code"> <pre><code class="highlight console"><span class="gp">$</span><span class="w"> </span><span class="nb">bin/rails </span>task_name <span class="gp">$</span><span class="w"> </span><span class="nb">bin/rails</span> <span class="s2">"task_name[value 1]"</span> <span class="c"># entire argument string should be quoted</span> <span class="gp">$</span><span class="w"> </span><span class="nb">bin/rails</span> <span class="s2">"task_name[value 1,value2,value3]"</span> <span class="c"># separate multiple args with a comma</span> <span class="gp">$</span><span class="w"> </span><span class="nb">bin/rails </span>db:nothing </code></pre> <button class="clipboard-button" data-clipboard-text="bin/rails task_name bin/rails "task_name[value 1]" # entire argument string should be quoted bin/rails "task_name[value 1,value2,value3]" # separate multiple args with a comma bin/rails db:nothing ">Copy</button> </div> <p>If you need to interact with your application models, perform database queries, and so on, your task should depend on the <code>environment</code> task, which will load your application code.</p><div class="interstitial code"> <pre><code class="highlight ruby"><span class="n">task</span> <span class="ss">task_that_requires_app_code: </span><span class="p">[</span><span class="ss">:environment</span><span class="p">]</span> <span class="k">do</span> <span class="no">User</span><span class="p">.</span><span class="nf">create!</span> <span class="k">end</span> </code></pre> <button class="clipboard-button" data-clipboard-text="task task_that_requires_app_code: [:environment] do User.create! end ">Copy</button> </div> </section> <hr> <footer aria-labelledby="heading-feedback" role="region"> <h2 id="heading-feedback">Feedback</h2> <p> You're encouraged to help improve the quality of this guide. </p> <p> Please contribute if you see any typos or factual errors. To get started, you can read our <a href="https://edgeguides.rubyonrails.org/contributing_to_ruby_on_rails.html#contributing-to-the-rails-documentation">documentation contributions</a> section. </p> <p> You may also find incomplete content or stuff that is not up to date. Please do add any missing documentation for main. Make sure to check <a href="https://edgeguides.rubyonrails.org">Edge Guides</a> first to verify if the issues are already fixed or not on the main branch. Check the <a href="ruby_on_rails_guides_guidelines.html">Ruby on Rails Guides Guidelines</a> for style and conventions. </p> <p> If for whatever reason you spot something to fix but cannot patch it yourself, please <a href="https://github.com/rails/rails/issues">open an issue</a>. </p> <p>And last but not least, any kind of discussion regarding Ruby on Rails documentation is very welcome on the <a href="https://discuss.rubyonrails.org/c/rubyonrails-docs">official Ruby on Rails Forum</a>. </p> </footer> </div> </article> </main> <hr class="hide" /> <footer id="complementary"> <div class="wrapper"> <p>This work is licensed under a <a href="https://creativecommons.org/licenses/by-sa/4.0/">Creative Commons Attribution-ShareAlike 4.0 International</a> License</p> <p>"Rails", "Ruby on Rails", and the Rails logo are trademarks of David Heinemeier Hansson. All rights reserved.</p> </div> </footer> <a href="#main-skip-link" class="back-to-top" data-turbo="false"><span class="visibly-hidden">Back to top</span></a> </body> </html>