uuidgen — command−line utility to create a new UUID value
uuidgen [ −r | −t ]
The uuidgen program creates (and prints) a new universally unique identifier (UUID) using the libuuid(3) library. The new UUID can reasonably be considered unique among all UUIDs created on the local system, and among UUIDs created on other systems in the past and in the future.
There are two types of UUID's which uuidgen can generate:
time-based UUID's and random-based UUID's. By default
uuidgen will
generate a random-based UUID if a high-quality random number
generator is present. Otherwise, it will chose a time-based
UUID. It is possible to force the generation of one of these
two UUID types by using the −r or −t options.
−rGenerate a random-based UUID. This method creates a
UUID consisting mostly of random bits. It requires that
the operating system have a high quality random number
generator, such as /dev/random.
−tGenerate a time-based UUID. This method creates a UUID based on the system clock plus the system's ethernet hardware address, if present.