Hello World
Hello World

Hello World

Tutorial Exercise


“Hello, World!” will get you writing some Crystal and familiarize yourself with the Exercism workflow. Completing it unlocks the rest of the Crystal Track.

Watch our "Introduction to Hello, World" video to get started 👇


The classical introductory exercise. Just say "Hello, World!".

"Hello, World!" is the traditional first program for beginning programming in a new language or environment.

The objectives are simple:

  • Modify the provided code so that it produces the string "Hello, World!".
  • Run the test suite and make sure that it succeeds.
  • Submit your solution and check it at the website.

If everything goes well, you will be ready to fetch your first real exercise.

Project Structure

  • src contains your solution to the exercise
  • spec contains the tests to run for the exercise

Running Tests

If you're in the right directory (i.e. the one containing src and spec), you can run the tests for that exercise by running crystal spec:

$ pwd

$ ls          spec               src

$ crystal spec

This will run all of the test files in the spec directory.

In each test file, all but the first test have been skipped.

Once you get a test passing, you can unskip the next one by changing pending to it.

Submitting Your Solution

Be sure to submit the source file in the src directory when submitting your solution:

$ exercism submit src/
Edit via GitHub The link opens in a new window or tab
Crystal Exercism

Ready to start Hello World?

Sign up to Exercism to learn and master Crystal with 21 concepts, 126 exercises, and real human mentoring, all for free.