Install lua on mac I’m not sure that whether Lua is built on mac originally. (Ok, tested on Mac OSX 10.9, there is Lua in it.) So I installed Lua via Homebrew. Install homebrew (optional) ruby -e "$(curl -fsSL https://raw.github.com/Homebrew/homebrew/go/install)" Install Lua by homebrew brew install lua Writing Lua You can use command: lua to interact with lua. (just like php -a or irb) print("Hello World") function fact(n) if n == 0 then return 1 else return n * fact(n-1) end end print("enter a number:") num = io.