1UUIDD(8) System Administration UUIDD(8)
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6 uuidd - UUID generation daemon
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9 uuidd [options]
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12 The uuidd daemon is used by the UUID library to generate universally
13 unique identifiers (UUIDs), especially time-based UUIDs, in a secure
14 and guaranteed-unique fashion, even in the face of large numbers of
15 threads running on different CPUs trying to grab UUIDs.
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18 -C, --cont-clock[=time]
19 Activate continuous clock handling for time based UUIDs. uuidd
20 could use all possible clock values, beginning with the daemon’s
21 start time. The optional argument can be used to set a value for
22 the max_clock_offset. This gurantees, that a clock value of a UUID
23 will always be within the range of the max_clock_offset.
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25 The option '-C' or '--cont-clock' enables the feature with a
26 default max_clock_offset of 2 hours.
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28 The option '-C<NUM>[hd]' or '--cont-clock=<NUM>[hd]' enables the
29 feature with a max_clock_offset of NUM seconds. In case of an
30 appended h or d, the NUM value is read in hours or days. The
31 minimum value is 60 seconds, the maximum value is 365 days.
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33 -d, --debug
34 Run uuidd in debugging mode. This prevents uuidd from running as a
35 daemon.
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37 -F, --no-fork
38 Do not daemonize using a double-fork.
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40 -k, --kill
41 If currently a uuidd daemon is running, kill it.
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43 -n, --uuids number
44 When issuing a test request to a running uuidd, request a bulk
45 response of number UUIDs.
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47 -P, --no-pid
48 Do not create a pid file.
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50 -p, --pid path
51 Specify the pathname where the pid file should be written. By
52 default, the pid file is written to {runstatedir}/uuidd/uuidd.pid.
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54 -q, --quiet
55 Suppress some failure messages.
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57 -r, --random
58 Test uuidd by trying to connect to a running uuidd daemon and
59 request it to return a random-based UUID.
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61 -S, --socket-activation
62 Do not create a socket but instead expect it to be provided by the
63 calling process. This implies --no-fork and --no-pid. This option
64 is intended to be used only with systemd(1). It needs to be enabled
65 with a configure option.
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67 -s, --socket path
68 Make uuidd use this pathname for the unix-domain socket. By
69 default, the pathname used is {runstatedir}/uuidd/request. This
70 option is primarily for debugging purposes, since the pathname is
71 hard-coded in the libuuid library.
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73 -T, --timeout number
74 Make uuidd exit after number seconds of inactivity.
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76 -t, --time
77 Test uuidd by trying to connect to a running uuidd daemon and
78 request it to return a time-based UUID.
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80 -h, --help
81 Display help text and exit.
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83 -V, --version
84 Print version and exit.
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87 Start up a daemon, print 42 random keys, and then stop the daemon:
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89 uuidd -p /tmp/uuidd.pid -s /tmp/uuidd.socket
90 uuidd -d -r -n 42 -s /tmp/uuidd.socket
91 uuidd -d -k -s /tmp/uuidd.socket
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94 The uuidd daemon was written by Theodore Ts’o <tytso@mit.edu>.
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97 uuid(3), uuidgen(1)
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100 For bug reports, use the issue tracker at
101 https://github.com/util-linux/util-linux/issues.
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104 The uuidd command is part of the util-linux package which can be
105 downloaded from Linux Kernel Archive
106 <https://www.kernel.org/pub/linux/utils/util-linux/>.
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110util-linux 2.39.2 2023-08-17 UUIDD(8)