Cloning VirtualBox VM

Go to Directory Where your disk file is stored.

cd /path/to/RubyRVM.vdi

Following is the syntax of the Cloning command:

VBoxManage clonevdi ExistingVDI NewVDI

For me the exact command is as follows:

VBoxManage clonevdi RubyRVM.vdi SqlRep.vdi

Create a new Virtual Machine in virtual machine and On the setup wizard when asked for disk use existing disk and specify the cloned disk path.