1.\" Copyright (c) 2002 Marcel Moolenaar 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 15.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 16.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 17.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 18.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 19.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 20.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 21.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 23.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24.\" 25.\" $FreeBSD$ 26.\" 27.Dd March 1, 2023 28.Dt UUIDGEN 1 29.Os 30.Sh NAME 31.Nm uuidgen 32.Nd generate universally unique identifiers 33.Sh SYNOPSIS 34.Nm 35.Op Fl 1 36.Op Fl r 37.Op Fl c 38.Op Fl n Ar count 39.Op Fl o Ar filename 40.Sh DESCRIPTION 41The 42.Nm 43utility by default generates a single DCE version 1 44universally unique identifier (UUID), 45also known as a globally unique identifier (GUID). 46The UUID is written to stdout by default. 47The following options can be used to change the behaviour of 48.Nm : 49.Bl -tag -width indent 50.It Fl 1 51This option only has effect if multiple identifiers are to be generated and 52instructs 53.Nm 54to not generate them in batch, but one at a time. 55.It Fl r 56This option controls creation of random UUID (version 4). 57.It Fl c 58This option controls creation of compact UUID (without hyphen). 59.It Fl n 60This option controls the number of identifiers generated. 61By default, multiple identifiers are generated in batch. 62The upper hard limit is 2048 63.Po see 64.Xr uuidgen 2 65.Pc . 66.It Fl o 67Redirect output to 68.Ar filename 69instead of stdout. 70.El 71.Pp 72Batched generation yields a dense set of identifiers in such a way that there 73is no identifier that is larger than the smallest identifier in the set and 74smaller than the largest identifier in the set and that is not already in the 75set. 76.Pp 77When generating the identifiers one at a time, the identifiers will be close 78to each other, but operating system latency and processing time will be 79reflected in the distance between two successive identifiers. 80.Sh EXIT STATUS 81.Ex -std 82.Sh SEE ALSO 83.Xr uuidgen 2 , 84.Xr uuid 3 85.Sh HISTORY 86The 87.Nm 88command first appeared in 89.Fx 5.0 . 90