Server and console:

$rails server or rails s 

Use if you want to access your application through a web browser. If it is local the direction usually is:

http://localhost:3000

$rails console or rails c 
Lets you interact with your Rails application from the command line in the development environment.

$rails console --sandbox 

Use it when you wish to test out some code without changing any data, any change will disappear when you quit.

$reload!

Use it if you changed some source code and want those changes reflected in the console without having to restart.

Testing:

$rails test or rails t

Run our test suite to verify if our test passes or not.

$rails generate integration_test site layout

Integration tests are used to test how various parts of your

application interact. Here we are creating an integration test

named "site_layout.test.rb" inside the "test/integration" folder.

$rails test: integration

Only runs a specific section of tests, in this case, it will only run

the integration tests.

$rails/rake routes

Routes:

To get a complete list of the available routes in your application.