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 May 23, 2012 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 n Ar count 37.Op Fl o Ar filename 38.Sh DESCRIPTION 39The 40.Nm 41utility by default generates a single DCE version 1 42universally unique identifier (UUID), 43also known as a globally unique identifier (GUID). 44The UUID is written to stdout by default. 45The following options can be used to change the behaviour of 46.Nm : 47.Bl -tag -width indent 48.It Fl 1 49This option only has effect if multiple identifiers are to be generated and 50instructs 51.Nm 52to not generate them in batch, but one at a time. 53.It Fl n 54This option controls the number of identifiers generated. 55By default, multiple identifiers are generated in batch. 56The upper hard limit is 2048 57.Po see 58.Xr uuidgen 2 59.Pc . 60.It Fl o 61Redirect output to 62.Ar filename 63instead of stdout. 64.El 65.Pp 66Batched generation yields a dense set of identifiers in such a way that there 67is no identifier that is larger than the smallest identifier in the set and 68smaller than the largest identifier in the set and that is not already in the 69set. 70.Pp 71When generating the identifiers one at a time, the identifiers will be close 72to each other, but operating system latency and processing time will be 73reflected in the distance between two successive identifiers. 74.Sh EXIT STATUS 75.Ex -std 76.Sh SEE ALSO 77.Xr uuidgen 2 , 78.Xr uuid 3 79.Sh HISTORY 80The 81.Nm 82command first appeared in 83.Fx 5.0 . 84