Up and running your first Ruby on Rails app [with troubleshooting]

Dheeraj jha
Intelligent computing
3 min readJul 26, 2021


Ruby on Rails are build on top of many existing language and frameworks and running it is not as simple in first go. This might cause to loose interest in new developer like me(in Ruby on Rails). I am writing quick way to install and fix any coming issue to run your first ruby on rail application.

Photo by Michael Dziedzic on Unsplash

For this demonstration, i will be using MacOS Mojave. However steps will be quite universal and you can run it with your corresponding OS once its clear to you.

Step 1 — Installing rbenv

To start, rbenvis package which will make sure it starts automatically on boot of your system. Your Homebrew can be used to install.

brew install rbenv

Now to make it load automatically in terminal, you need to update your bash configuration file by editing .bash_profilein your home directory

nano .bash_profile

and add following line at bottom of file.

eval "$(rbenv init -)"

Save the file and quit.

Now apply changes by reloading your bash profile. To do so, run

source ~/.bash_profile

Step 2 — Ruby installation

Now you can use rbenv to install Ruby. To do so, run following command, this will install latest version of Ruby.

rbenv install

to set the specific ruby version to global, you can run command

rbenv global 2.6.3

Now you can verify installation using

ruby -v

Step 3 — Setting up gems

At the time of gem installation, it would generate local documentation thus consuming more time and space, to turn this off, first run following command.

echo "gem: --no-document" > ~/.gemrc

Now go ahead and install bundler

gem install bundler

Step 4 — Installing Rails

Rails can be installed using gem install rail command and if you want to specify version, you can do so by passing -v flag.

gem install rails -v 6.0.0

to activate new changes in directory, you need to rehash. to do so

rbenv rehash

Now you can verify Rails installation by command

rails -v

Step 5 — Creating first Application

lets create first application by creating directory first say projects directory and application name will be blog

~/projects$ rails new blog

this will create new application named blog which will have all Ruby on rail structure along with all required gems installed.

Step 6 — Running your application

To run your application in development environment, you need to go inside your project directory using command line.

Once inside, you need to run

rails server

and this should output

=> Booting Puma
=> Rails 6.1.4 application starting in development
=> Run `bin/rails server --help` for more startup options
Puma starting in single mode...
* Puma version: 5.3.2 (ruby 2.6.3-p62) ("Sweetnighter")
* Min threads: 5
* Max threads: 5
* Environment: development
* PID: 64574
* Listening on
* Listening on http://[::1]:3000
Use Ctrl-C to stop
Started GET "/" for at 2021-07-26 22:30:29 +0530
(5.4ms) SELECT sqlite_version(*)
Processing by Rails::WelcomeController#index as HTML
Rendering /Users/userName/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/railties-6.1.4/lib/rails/templates/rails/welcome/index.html.erb
Rendered /Users/userName/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/railties-6.1.4/lib/rails/templates/rails/welcome/index.html.erb (Duration: 9.6ms | Allocations: 532)
Completed 200 OK in 49ms (Views: 18.1ms | ActiveRecord: 0.0ms | Allocations: 4409)

Now you can visit and see your first Rails application running.


While you ran rails server command, you might face issue like Webpacker configuration file not found. To resolve this issue. you have to follow instruction below.

Install webpacker

bundle exec rails webpacker:install

This command itself require yarn to complete, and yarn require nodejs to be installed.

To install nodejs: https://nodejs.org/en/download/

Once nodejs is installed, run

npm install --global yarn

After both of above done setup, you can re-run `bundle exec rails webpacker:install and you setup is completed.

You can now run rails server command and open your rails application in browser

If you find this helpful, you can share/tweet so devs can find easily.

Troubleshooting step i have separately mentioned in my stackoverflow answer as well.



Dheeraj jha
Intelligent computing

DevOps Engineer | Team lead | AWS | Docker | CI/CD | Gitlab-CI