vendor/rails/railties/doc/guides/source/command_line.txt

   1 A Guide to The Rails Command Line
   2 =================================
   3
   4 Rails comes with every command line tool you'll need to
   5
   6 * Create a Rails application
   7 * Generate models, controllers, database migrations, and unit tests
   8 * Start a development server
   9 * Mess with objects through an interactive shell
  10 * Profile and benchmark your new creation
  11
  12 ... and much, much more! (Buy now!)
  13
  14 This tutorial assumes you have basic Rails knowledge from reading the Getting Started with Rails Guide.
  15
  16 == Command Line Basics ==
  17
  18 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:
  19
  20 * console
  21 * server
  22 * rake
  23 * generate
  24 * rails
  25
  26 Let's create a simple Rails application to step through each of these commands in context.
  27
  28 === rails ===
  29
  30 The first thing we'll want to do is create a new Rails application by running the `rails` command after installing Rails.
  31
  32 NOTE: You know you need the rails gem installed by typing `gem install rails` first, right? Okay, okay, just making sure.
  33
  34 [source,shell]
  35 ------------------------------------------------------
  36 $ rails commandsapp
  37
  38      create
  39      create  app/controllers
  40      create  app/helpers
  41      create  app/models
  42      ...
  43      ...
  44      create  log/production.log
  45      create  log/development.log
  46      create  log/test.log
  47 ------------------------------------------------------
  48
  49 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.
  50
  51 NOTE: This output will seem very familiar when we get to the `generate` command. Creepy foreshadowing!
  52
  53 === server ===
  54
  55 Let's try it! The `server` 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.
  56
  57 NOTE: WEBrick isn't your only option for serving Rails. We'll get to that in a later section. [XXX: which section]
  58
  59 Here we'll flex our `server` command, which without any prodding of any kind will run our new shiny Rails app:
  60
  61 [source,shell]
  62 ------------------------------------------------------
  63 $ cd commandsapp
  64 $ ./script/server
  65 => Booting WEBrick...
  66 => Rails 2.2.0 application started on http://0.0.0.0:3000
  67 => Ctrl-C to shutdown server; call with --help for options
  68 [2008-11-04 10:11:38] INFO  WEBrick 1.3.1
  69 [2008-11-04 10:11:38] INFO  ruby 1.8.5 (2006-12-04) [i486-linux]
  70 [2008-11-04 10:11:38] INFO  WEBrick::HTTPServer#start: pid=18994 port=3000
  71 ------------------------------------------------------
  72
  73 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 http://localhost:3000. I'll wait.
  74
  75 See? Cool! It doesn't do much yet, but we'll change that.
  76
  77 === generate ===
  78
  79 The `generate` command uses templates to create a whole lot of things. You can always find out what's available by running `generate` by itself. Let's do that:
  80
  81 [source,shell]
  82 ------------------------------------------------------
  83 $ ./script/generate
  84 Usage: ./script/generate generator [options] [args]
  85
  86 ...
  87 ...
  88
  89 Installed Generators
  90   Builtin: controller, integration_test, mailer, migration, model, observer, performance_test, plugin, resource, scaffold, session_migration
  91
  92 ...
  93 ...
  94 ------------------------------------------------------
  95
  96 NOTE: You can install more generators through generator gems, portions of plugins you'll undoubtedly install, and you can even create your own!
  97
  98 Using generators will save you a large amount of time by writing *boilerplate code* for you -- necessary for the darn thing to work, but not necessary for you to spend time writing. That's what we have computers for, right?
  99
 100 Let's make our own controller with the controller generator. But what command should we use? Let's ask the generator:
 101
 102 NOTE: All Rails console utilities have help text. For commands that require a lot of input to run correctly, you can just try the command without any parameters (like `rails` or `./script/generate`). For others, you can try adding `--help` or `-h` to the end, as in `./script/server --help`.
 103
 104 [source,shell]
 105 ------------------------------------------------------
 106 $ ./script/generate controller
 107 Usage: ./script/generate controller ControllerName [options]
 108
 109 ...
 110 ...
 111
 112 Example:
 113     `./script/generate controller CreditCard open debit credit close`
 114
 115     Credit card controller with URLs like /credit_card/debit.
 116         Controller: app/controllers/credit_card_controller.rb
 117         Views:      app/views/credit_card/debit.html.erb [...]
 118         Helper:     app/helpers/credit_card_helper.rb
 119         Test:       test/functional/credit_card_controller_test.rb
 120
 121 Modules Example:
 122     `./script/generate controller 'admin/credit_card' suspend late_fee`
 123
 124     Credit card admin controller with URLs /admin/credit_card/suspend.
 125         Controller: app/controllers/admin/credit_card_controller.rb
 126         Views:      app/views/admin/credit_card/debit.html.erb [...]
 127         Helper:     app/helpers/admin/credit_card_helper.rb
 128         Test:       test/functional/admin/credit_card_controller_test.rb
 129 ------------------------------------------------------
 130
 131 Ah, the controller generator is expecting parameters in the form of `generate controller ControllerName action1 action2`. Let's make a `Greetings` controller with an action of *hello*, which will say something nice to us.
 132
 133 [source,shell]
 134 ------------------------------------------------------
 135 $ ./script/generate controller Greeting hello
 136      exists  app/controllers/
 137      exists  app/helpers/
 138      create  app/views/greeting
 139      exists  test/functional/
 140      create  app/controllers/greetings_controller.rb
 141      create  test/functional/greetings_controller_test.rb
 142      create  app/helpers/greetings_helper.rb
 143      create  app/views/greetings/hello.html.erb
 144 ------------------------------------------------------
 145
 146 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. All from one command!
 147