The UUID is a 128-bit universally unique identifier which is burned on the motherboard on a system. It’s typically represented as a 32 character string separated into groups of 8, 4, 4, 4, 12 characters by a dash.
An example of a UUID is:
This can be assumed to be unique to a computer. The only time I encountered collisions were when two Dell servers did not have the asset tag set which suggests that the UUID is a function of certain parameters on these servers.
To get the UUID on Windows, the simplest way is to use PowerShell:
get-wmiobject Win32_ComputerSystemProduct | Select-Object -ExpandProperty UUID
To get the UUID on Linux or FreeBSD, use dmidecode which can be installed through mots package managers (yum, apt-get, pacman, etc) or through ports at
dmidecode | grep -i uuid
To get the UUID on VMWare ESXi or vSphere, login via SSH and run:
esxcfg-info | grep -i uuid
You will see a bunch of UUIDs, most of which pertain to disks/volumes. What you are looking for is: