Some interesting facts

• Awesome WM is mainly written in Lua and uses it as its configuration file format

• Cheat Engine, memory editor/debugger uses Lua to be embedded in its "cheat tables"

• Conky, a Linux system monitor, uses Lua for advanced graphics

• CRYENGINE, game engine, uses Lua for user scripts

• Garry's Mod uses Lua.

Example of "Hello World" code written in Lua compared to other programming languages

Lua

print("Hello World!")

JavaScript

"use strict"
console.log("Hello world!");

Haskell

module Main where

main :: IO ()
main = putStrLn "Hello, World!"

Python 3

print("Hello, world!")

Ruby

puts "Hello world!"