uuidgen(1) [sunos man page]

UUIDGEN(1)							   User Commands							UUIDGEN(1)

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 reason-
       ably 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)

Check Out this Related Man Page

UUID_GENERATE(3)						    Libuuid API 						  UUID_GENERATE(3)

NAME

       uuid_generate, uuid_generate_random, uuid_generate_time - create a new unique UUID value

SYNOPSIS

       #include <uuid/uuid.h>

       void uuid_generate(uuid_t out);
       void uuid_generate_random(uuid_t out);
       void uuid_generate_time(uuid_t out);

DESCRIPTION

       The uuid_generate function creates a new universally unique identifier (UUID).  The uuid will be generated based on high-quality randomness
       from /dev/urandom, if available.  If it is not available, then uuid_generate will use an alternative algorithm which uses the current time,
       the local ethernet MAC address (if available), and random data generated using a pseudo-random generator.

       The  uuid_generate_random  function  forces  the  use  of the all-random UUID format, even if a high-quality random number generator (i.e.,
       /dev/urandom) is not available, in which case a pseudo-random generator will be substituted.  Note that the use of a pseudo-random  genera-
       tor may compromise the uniqueness of UUIDs generated in this fashion.

       The  uuid_generate_time function forces the use of the alternative algorithm which uses the current time and the local ethernet MAC address
       (if available).	This algorithm used to be the default one used to generate UUID, but because of the use of the ethernet  MAC  address,	it
       can leak information about when and where the UUID was generated.  This can cause privacy problems in some applications, so the uuid_gener-
       ate function only uses this algorithm if a high-quality source of randomness is not available.

       The UUID is 16 bytes (128 bits) long, which gives approximately 3.4x10^38 unique values (there are approximately 10^80 elementary particles
       in  the	universe according to Carl Sagan's Cosmos).  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.

RETURN VALUE

       The newly created UUID is returned in the memory location pointed to by out.

CONFORMING TO

       OSF DCE 1.1

AUTHOR

       Theodore Y. Ts'o

AVAILABILITY

       libuuid is part of the util-linux package since version 2.15.1 and is available from ftp://ftp.kernel.org/pub/linux/utils/util-linux/.

SEE ALSO

       uuid(3), uuidgen(1), uuid_clear(3), uuid_compare(3), uuid_copy(3), uuid_is_null(3), uuid_parse(3), uuid_time(3), uuid_unparse(3)

util-linux							     May 2009							  UUID_GENERATE(3)

Linux and UNIX Man Pages

uuidgen(1) [sunos man page]

Check Out this Related Man Page