-- to install: 
--   (Debian/Ubuntu) apt-get install lua
--   (Fedora/CentOS) yum install lua
--   (source code)   curl -R -O http://www.lua.org/ftp/lua-5.3.4.tar.gz | tar xz - 
--                   cd lua-5.3.4
--                   make linux
--
-- to execute: 
--   lua hello.lua

io.write("Hello world, from ",_VERSION,"!\n")