uuidgen(1) - create a new UUID value

pangolinsos

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 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.	Other‐
       wise, 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, there‐
       fore, a predictable value which may be useful when UUIDs are being used as han‐
       dles  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)