Article originally published here :https://alsohelp.com/blog/how-to-create-tons-rails-applications

1. Motivation

AtBootrAils, we are using this script every (working !) day. It allows you to :

• grab any concept,
• isolate a bug quickly,
• play with new Rails features,

... without any side effect.

Side note for beginners : It's also an excellent way to improve your Ruby-on-Rails skills. The more you create new apps from scratch, the more you understand the directory structure, the philosophy, and the internals of Rails.

2. The trick

Open~.bash_profile on your linux-based computer.

We will create a bash function, namedcnra (an acronym that means "create new rails application"). Acronyms are very handy to avoid remembering every shortcut.

# inside ~.bash_profile## Usage :# $> cnra myapp 7.0.0 --minimal --database=postgresql#cnra(){# create dir, dive into dir, require desired Rails versionmkdir-p--"$1"&&cd-P--"$1"echo"source 'https://rubygems.org'"> Gemfileecho"gem 'rails', '$2'">> Gemfile# install rails, create new rails app  bundleinstallbundleexecrails new.--force${@:3:99}  bundle update# Create a default controllerecho"class HomeController < ApplicationController"> app/controllers/home_controller.rbecho"end">> app/controllers/home_controller.rb# Create a default routeecho"Rails.application.routes.draw do"> config/routes.rbecho'  get "home/index"'>> config/routes.rbecho'  root to: "home#index"'>> config/routes.rbecho'end'>> config/routes.rb# Create a default viewmkdirapp/views/homeecho'<h1>This is h1 title</h1>'> app/views/home/index.html.erb# Create database and schema.rb  bin/rails db:create  bin/rails db:migrate}

Note the trick${@:3:99} that means "all remaining CLI args, from the 3rd one to the last one."

Otherwise, comments should be self-explanatory. If not, justcontact us :)

Now type

$>source ~/.bash_profile

So that your terminal will be aware of what changed inside your.bash_profile.

Usage

Open your terminal

$> cnra myapp 7.0.0--minimal-d=postgresql

1st CLI arg is "myapp" : the name of the new app
2nd CLI arg is 7.0.0 : the version of Rails you want to try
3rd CLI arg is --minimal -d=postgresql : PostGre is a production-ready database you can easily use locally.

Note that--minimal and-d=postgresql are optionals.

Going further

We personally like the minimal flag (to avoid all the default gems we probably won't need), and the "postgresql" database - a production-ready, widely used database in the Ruby-on-Rails world. So we use another shortcut, based on the previous one.

cnra7mp(){  cnra myapp 7.0.0--minimal-d=postgresql}

All we have to do now each time we want to try something with Rails is the following :

$/workspace> cnra7mp$/workspace/myapp> bin/rails server

Andvoilà ! A new Rails application up and running, no need to create the database, or build a default welcome page : our app is ready for experimentations.

All available options

If you need to know all the options when creating a new Rails application, seehttps://www.bootrails.com/blog/rails-new-options/

Enjoy !