NAME

       dbus-uuidgen - Utility to generate UUIDs

SYNOPSIS

       dbus-uuidgen [--version] [--ensure [=FILENAME]] [--get [=FILENAME]]

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").

       See http://www.freedesktop.org/software/dbus/ for more information about D-Bus.

       The primary usage of dbus-uuidgen is to run in the post-install script of a D-Bus package
       like this:

             dbus-uuidgen --ensure

       This will ensure that /var/lib/dbus/machine-id exists and has the uuid in it. It won't
       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 running 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 it 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. Don't try to change this file. Also, don't 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:

       --get[=FILENAME]
           If a filename is not given, defaults to localstatedir/lib/dbus/machine-id
           (localstatedir is usually /var). If this file exists and is valid, the uuid in the
           file is printed on stdout. Otherwise, the command exits with a nonzero status.

       --ensure[=FILENAME]
           If a filename is not given, defaults to localstatedir/lib/dbus/machine-id
           (localstatedir is usually /var). 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.

       --version
           Print the version of dbus-uuidgen

AUTHOR

       See http://www.freedesktop.org/software/dbus/doc/AUTHORS

BUGS

       Please send bug reports to the D-Bus mailing list or bug tracker, see
       http://www.freedesktop.org/software/dbus/