NAME

       uuidgen - create a new UUID value

SYNOPSIS

       uuidgen [options]

DESCRIPTION

       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 three types of UUIDs which uuidgen can generate: time-based UUIDs, random-based
       UUIDs, and hash-based UUIDs. By default uuidgen will generate a random-based UUID if a
       high-quality random number generator is present. Otherwise, it will choose a time-based
       UUID. It is possible to force the generation of one of these first two UUID types by using
       the --random or --time options.

       The third type of UUID is generated with the --md5 or --sha1 options, followed by
       --namespace namespace and --name name. The namespace may either be a well-known UUID, or
       else an alias to one of the well-known UUIDs defined in RFC 4122, that is @dns, @url,
       @oid, or @x500. The name is an arbitrary string value. The generated UUID is the digest of
       the concatenation of the namespace UUID and the name value, hashed with the MD5 or SHA1
       algorithms. It is, therefore, a predictable value which may be useful when UUIDs are being
       used as handles or nonces for more complex values or values which shouldn’t be disclosed
       directly. See the RFC for more information.

OPTIONS

       -r, --random
           Generate a random-based UUID. This method creates a UUID consisting mostly of random
           bits. It requires that the operating system has a high quality random number
           generator, such as /dev/random.

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

       -h, --help
           Display help text and exit.

       -V, --version
           Print version and exit.

       -m, --md5
           Use MD5 as the hash algorithm.

       -s, --sha1
           Use SHA1 as the hash algorithm.

       -n, --namespace namespace
           Generate the hash with the namespace prefix. The namespace is UUID, or '@ns' where
           "ns" is well-known predefined UUID addressed by namespace name (see above).

       -N, --name name
           Generate the hash of the name.

       -C, --count num
           Generate multiple UUIDs using the enhanced capability of the libuuid to cache
           time-based UUIDs, thus resulting in improved performance. However, this holds no
           significance for other UUID types.

       -x, --hex
           Interpret name name as a hexadecimal string.

CONFORMING TO

       OSF DCE 1.1

EXAMPLES

       uuidgen --sha1 --namespace @dns --name "www.example.com"

AUTHORS

       uuidgen was written by Andreas Dilger for libuuid(3).

SEE ALSO

       uuidparse(1), libuuid(3), RFC 4122 <https://tools.ietf.org/html/rfc4122>

REPORTING BUGS

       For bug reports, use the issue tracker at https://github.com/util-linux/util-linux/issues.

AVAILABILITY

       The uuidgen command is part of the util-linux package which can be downloaded from Linux
       Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.