# uuidd - UUID generation daemon - man(8) - [phpMan]

[_UUIDD_(8)](https://www.chedong.com/phpMan.php/man/UUIDD/8/markdown)                                System Administration                               [_UUIDD_(8)](https://www.chedong.com/phpMan.php/man/UUIDD/8/markdown)

## NAME
       uuidd - UUID generation daemon

## SYNOPSIS
       **uuidd **[options]

## DESCRIPTION
       The **uuidd **daemon is used by the UUID library to generate universally unique identifiers
       (UUIDs), especially time-based UUIDs, in a secure and guaranteed-unique fashion, even in the
       face of large numbers of threads running on different CPUs trying to grab UUIDs.

## OPTIONS
### -C --cont-clock
           Activate continuous clock handling for time based UUIDs. **uuidd **could use all possible
           clock values, beginning with the daemon’s start time. The optional argument can be used
           to set a value for the max_clock_offset. This gurantees, that a clock value of a UUID
           will always be within the range of the max_clock_offset.

           The option '-C' or '--cont-clock' enables the feature with a default max_clock_offset of
           2 hours.

           The option '-C<NUM>[hd]' or '--cont-clock=<NUM>[hd]' enables the feature with a
           max_clock_offset of NUM seconds. In case of an appended h or d, the NUM value is read in
           hours or days. The minimum value is 60 seconds, the maximum value is 365 days.

### -d --debug
           Run **uuidd **in debugging mode. This prevents **uuidd **from running as a daemon.

### -F --no-fork
           Do not daemonize using a double-fork.

### -k --kill
           If currently a uuidd daemon is running, kill it.

### -n --uuids _
           When issuing a test request to a running **uuidd**, request a bulk response of _number_ UUIDs.

### -P --no-pid
           Do not create a pid file.

### -p --pid _
           Specify the pathname where the pid file should be written. By default, the pid file is
           written to _{runstatedir}/uuidd/uuidd.pid_.

### -q --quiet
           Suppress some failure messages.

### -r --random
           Test uuidd by trying to connect to a running uuidd daemon and request it to return a
           random-based UUID.

### -S --socket-activation
           Do not create a socket but instead expect it to be provided by the calling process. This
           implies **--no-fork **and **--no-pid**. This option is intended to be used only with [**systemd**(1)](https://www.chedong.com/phpMan.php/man/systemd/1/markdown).
           It needs to be enabled with a configure option.

### -s --socket _
           Make uuidd use this pathname for the unix-domain socket. By default, the pathname used is
           _{runstatedir}/uuidd/request_. This option is primarily for debugging purposes, since the
           pathname is hard-coded in the **libuuid **library.

### -T --timeout _
           Make **uuidd **exit after _number_ seconds of inactivity.

### -t --time
           Test **uuidd **by trying to connect to a running uuidd daemon and request it to return a
           time-based UUID.

### -h --help
           Display help text and exit.

### -V --version
           Print version and exit.

## EXAMPLE
       Start up a daemon, print 42 random keys, and then stop the daemon:

           uuidd -p /tmp/uuidd.pid -s /tmp/uuidd.socket
           uuidd -d -r -n 42 -s /tmp/uuidd.socket
           uuidd -d -k -s /tmp/uuidd.socket

## AUTHOR
       The **uuidd **daemon was written by Theodore Ts’o <<tytso@mit.edu>>.

## SEE ALSO
       [**uuid**(3)](https://www.chedong.com/phpMan.php/man/uuid/3/markdown), [**uuidgen**(1)](https://www.chedong.com/phpMan.php/man/uuidgen/1/markdown)

## REPORTING BUGS
       For bug reports, use the issue tracker at <https://github.com/util-linux/util-linux/issues>.

## AVAILABILITY
       The **uuidd **command is part of the util-linux package which can be downloaded from Linux Kernel
       Archive <<https://www.kernel.org/pub/linux/utils/util-linux/>>.

util-linux 2.39.3                            2023-11-21                                     [_UUIDD_(8)](https://www.chedong.com/phpMan.php/man/UUIDD/8/markdown)