virt-what is a shell script which can be used to detect if the program
is running in a virtual machine.

The program prints out a list of "facts" about the virtual machine,
derived from heuristics. One fact is printed per line.

If nothing is printed and the script exits with code 0 (no error),
then it can mean either that the program is running on bare-metal or
the program is running inside a type of virtual machine which we don't
know about or cannot detect.

Current types of virtualization detected:

- hyperv Microsoft Hyper-V
- kvm Linux Kernel Virtual Machine (KVM)
- openvz OpenVZ or Virtuozzo
- powervm_lx86 IBM PowerVM Lx86 Linux/x86 emulator
- qemu QEMU (unaccelerated)
- uml User-Mode Linux (UML)
- virtage Hitachi Virtualization Manager (HVM) Virtage LPAR
- virtualbox VirtualBox
- virtualpc Microsoft VirtualPC
- vmware VMware
- xen Xen
- xen-dom0 Xen dom0 (privileged domain)
- xen-domU Xen domU (paravirtualized guest domain)
- xen-hvm Xen guest fully virtualized (HVM)