Trivia about "Hello, world!" A "Hello, world!" program is generally a computer program that outputs or displays the message "Hello, world!". This program is very simple to write in many programming languages, and is often used to illustrate a language's basic syntax. "Hello, world!" programs are often the first a student learns to write in a given language, and they can also be used as a sanity test to ensure computer software intended to compile or run source code is correctly installed, and that its operator understands how to use it.