ref: 20fb343d80f9d83122d2d37c78aad1cd8a944448
dir: /src/lua/test/env.lua/
-- read environment variables as if they were global variables
local f=function (t,i) return os.getenv(i) end
setmetatable(getfenv(),{__index=f})
-- an example
print(a,USER,PATH)