Reinstall OS X (Yosemite) without Internet Connection I have got very slow internet connection. Last time, it took me 8 hours to download the Yosemite installation files.
Is there anyway to clone a clean copy of OS X to another drive?

I have tried rsync in the Terminal after Bootup + Option. The rsync command is not available
You can use a third-party utility like Carbon Copy Cloner or you can even use Disk Utility in OS X to create and restore OS X Images.  There is also hdiutil and asr if you want to work from the command line.  In a Terminal type man hdiutil and man asr to bring up their man pages.