Actually, I've had the same idea of using 'file' command but it's not available on windows OS which will make my script unmovable

I think you are confusing "not available" with "not installed by default". But if the latter is a reason for you script to be unmoveable, I urge you to not write your program in Perl. After all, perl is as unavailable on Windows as file is: neither comes by default with the OS. But both have been ported to the platform.