There are some ‘hello world’ programs.

C++

#include <iostream>

int main() {
	std::cout << "hello world!" << std::endl;
	return 0;
}

Shell Script

#!/bn/sh

echo "hello world!"

Python

#!/usr/bin/env python

print("hello world!");

Go

package main

import (
	"fmt"
)

func main() {
	fmt.Println("hello world!")
}