Ruby on Rails Q & A


What is the Rails command line and what are its main commands?

The Rails command line interface (CLI) is a powerful set of tools provided by Rails to help developers manage, configure, and operate their applications more efficiently. Here’s a rundown of the Rails CLI and its prominent commands:


  1. rails new [APP_NAME]: The starting point for any Rails application. This command initializes a new Rails project with a standard directory structure, configuration files, and more.


  1. rails server (or rails s): Launches a local development server, usually Puma by default, so you can view and test your application in a browser. The server typically runs on `localhost:3000`.


  1. rails generate (or rails g): A powerful command used to automatically generate boilerplate code and files. Common sub-commands include:


   – `rails g model [MODEL_NAME]`: Generates a new ActiveRecord model along with its associated migration file.

   – `rails g controller [CONTROLLER_NAME]`: Creates a new controller with specified actions.

   – `rails g migration [MIGRATION_NAME]`: Constructs a new database migration file.


  1. rails db:migrate: Executes pending database migrations. This command alters the database schema in line with the migration files’ instructions.


  1. rails db:seed: Populates the database using data specified in the `db/seeds.rb` file.


  1. rails console (or rails c): Opens an interactive Ruby shell with the Rails environment loaded, allowing developers to interact with their application’s data and classes directly.


  1. rails routes: Lists all the defined routes in the application, which is very handy for reviewing and debugging routing issues.


  1. rails db:rollback: Undoes the last database migration. This can be helpful when you need to correct or modify a recent migration.


  1. rails test: Runs the test suite of the application, ensuring that the application’s logic meets the specified requirements and functions correctly.


  1. rails assets precompile: Prepares and optimizes static assets (like CSS, JavaScript, and images) for production deployment.


  1. rails db: create and rails db:drop: Creates and drops the application’s database, respectively.


The Rails command line is a Swiss Army knife for Rails developers. It streamlines many common tasks, from scaffolding out new components to managing the database and assets. Familiarity with these commands is crucial for efficient Rails development, as they’re frequently used throughout an application’s lifecycle.

Previously at
Flag Argentina
time icon
Senior Software Engineer with a focus on remote work. Proficient in Ruby on Rails. Expertise spans y6ears in Ruby on Rails development, contributing to B2C financial solutions and data engineering.