Erlang Hello World Example: How To Write, Compile and Execute Erlang Program on Linux OS

Question: I would like to understand the basics of how to write and execute Erlang program on Linux OS. Can you explain it with a simple example?

Answer: In this article, let us review very quickly how to write a basic Hello World Erlang program, Compile and execute erlang program on Linux or Unix OS.

If you are new to Erlang programming language, read this erlang programming page on wikipedia.

1. Write a Hello World Erlang Program

Create the helloworld program using a Vim editor as shown below.

$ vim helloworld.erl

% hello world program
-module(helloworld).
-export([start/0]).

start() ->
    io:fwrite("Hello, world!\n").

Note: Comment in Erlang starts with %.

2. Make sure Erlang command line interpreter is installed on your system

Make sure Erlang compiler is installed on your system as shown below.

$ whereis erlc
erlc: /usr/bin/erlc /usr/share/man/man1/erlc.1.gz

Installing erlang Compiler

If you don’t have erlang compiler, install it as shown below.

$ sudo apt-get install erlang-ic

3. Compile the erlang program

Compile the erlang hello world which will create the executable.

$ erlc helloworld.erl

$ ls
helloworld.beam  helloworld.erl 

4. Execute the erlang Program

Execute as shown below.

$ erl -noshell -s helloworld start -s init stop
Hello, world!

5. Erlang one liner

You can also execute erlang from the command line as shown below. This will print Hello World!.

$ erl -noshell -eval 'io:fwrite("Hello, World!\n"), init:stop().'
Hello, World!