Our First Elixir Program

Dating back to the 1970s, the first program for learners trying out a new programming language has been to print the text Hello, world! on screen.

Let’s try the same for Elixir. Let’s see different ways to do it.

Scripting mode

Go ahead and type the following code in an IDE / Text Editor of your choice.

IO.puts("Hello, world!")

Save the file as hello_world.exs.

To run the program, type the following command in your terminal / command prompt:

elixir hello_world.exs

The file type .exs indicates that it’s an Elixir script. You should see the following output printed on screen:

Hello, world!

Compilation

Elixir can be both compiled and interpreted. Compiled code is faster than interpreted code, and it can be run on the BEAM VM, which is what we’ll be working with in the coming lessons.

For compiling the code, we’ll write it in .ex files, which indicates to the elixir compiler that the file contains source code for an Elixir program that will be compiled to be run on the BEAM VM.

Let’s write some code and compile it:

defmodule HelloWorld do
  def hello do
    IO.puts("Hello, world!")
  end
end

Save the file as hello_world_123.ex. Now change to the directory where the file is saved and compile the file with the following command:

# Compile the file to be run on the BEAM VM
elixirc hello_world.ex

We should see a new file named Elixir.HelloWorld.beam in the same directory. This file contains the compiled bytecode for the program, which can be executed on the BEAM VM. If you’ve used languages like Java, this is similar