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 concatentation 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  have  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
              Display version information and exit.

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

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

       -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.

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

CONFORMING TO

       OSF DCE 1.1

EXAMPLES

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

AUTHOR

       uuidgen was written by Andreas Dilger for libuuid.

SEE ALSO

       libuuid(3), RFC 4122

AVAILABILITY

       The   uuidgen   command   is   part   of   the    util-linux    package    and    is    available    from
       https://www.kernel.org/pub/linux/utils/util-linux/.

util-linux                                          June 2011                                         UUIDGEN(1)