1*572c4311Sfengbojiang-- read environment variables as if they were global variables 2*572c4311Sfengbojiang 3*572c4311Sfengbojianglocal f=function (t,i) return os.getenv(i) end 4*572c4311Sfengbojiangsetmetatable(getfenv(),{__index=f}) 5*572c4311Sfengbojiang 6*572c4311Sfengbojiang-- an example 7*572c4311Sfengbojiangprint(a,USER,PATH) 8