dbus-uuidgen(1) User Commands dbus-uuidgen(1)NAMEdbus-uuidgen - Utility to generate UUIDs
SYNOPSISdbus-uuidgen [--ensure=file] [--get=file] [--version]
DESCRIPTION
The dbus-uuidgen command generates or reads a universally unique ID.
Note that the D-Bus UUID has no relationship to RFC 4122 and does not
generate UUIDs compatible with that spec. Many systems have a separate
command for that (often called "uuidgen").
The primary usage of dbus-uuidgen is to run in the post-install script
of a D-Bus package as shown in the example section of this document.
This will ensure that /var/lib/dbus/machine-id exists and has the uuid
in it. It will not overwrite an existing uuid, since this id should
remain fixed for a single machine until the next reboot at least.
The important properties of the machine UUID are that 1) it remains
unchanged until the next reboot and 2) it is different for any two run‐
ning instances of the OS kernel. That is, if two processes see the
same UUID, they should also see the same shared memory, UNIX domain
sockets, local X displays, localhost.localdomain resolution, process
IDs, and so forth.
If you run dbus-uuidgen with no options it just prints a new uuid made
up out of thin air.
If you run dbus-uuidgen with --get, it prints the machine UUID by
default, or the UUID in the specified file if you specify a file.
If you try to change an existing machine-id on a running system, it
will probably result in bad things happening. Do not try to change
this file. Also, do not make it the same on two different systems; it
needs to be different anytime there are two different kernels running.
The UUID should be different on two different virtual machines, because
there are two different kernels.
OPTIONS
The following options are supported:
--ensure=file
If a file is not given, defaults to /var/lib/dbus/machine-id. If
this file exists then it will be validated, and a failure code
returned if it contains the wrong thing. If the file does not
exist, it will be created with a new uuid in it. On success,
prints no output.
--get=file
If a file is not given, defaults to /var/lib/dbus/machine-id. If
this file exists and is valid, the uuid in the file is printed on
stdout. Otherwise, the command exits with a nonzero status.
--version
Print the version of dbus-uuidgenEXAMPLES
Example 1: The primary usage of dbus-uuidgen is to run in the post-
install script of a D-Bus package
dbus-uuidgen--ensure
EXIT STATUS
The following exit values are returned:
0 Application exited successfully
>0 Application exited with failure
FILES
The following files are used by this application:
/usr/bin/dbus-uuidgen Executable for dbus-uuidgen
/var/lib/dbus/machine-id File containing the uuid generated for
this machine.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Availability │system/library/dbus │
├─────────────────────────────┼─────────────────────────────┤
│Interface stability │Volatile │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSO
More information can be found at:
http://www.freedesktop.org/software/dbus/
dbus-binding-tool(1), dbus-cleanup-sockets(1), dbus-daemon(1), dbus-
launch(1), dbus-monitor(1), dbus-send(1), libdbus-glib-1(3),
attributes(5)NOTES
For authorship information refer to http://www.freedesktop.org/soft‐
ware/dbus/doc/AUTHORS. Updated by Brian Cameron, Sun Microsystems
Inc., 2007.
Please send bug reports to the D-Bus mailing list or bug tracker, see
http://www.freedesktop.org/software/dbus/
SunOS 5.11 25 Feb 2009 dbus-uuidgen(1)
