The
uuidgen program creates 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.
Generate 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.
-t
Generate a time-based UUID. This method creates a UUID based on the system
clock plus the system’s ethernet hardware address, if present.