1.\" $NetBSD: gpt.8,v 1.5 2009/03/11 18:02:00 joerg Exp $ 2.\" 3.\" Copyright (c) 2002 Marcel Moolenaar 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26.\" 27.\" $FreeBSD: src/sbin/gpt/gpt.8,v 1.17 2006/06/22 22:22:32 marcel Exp $ 28.\" 29.Dd June 22, 2006 30.Dt GPT 8 31.Os 32.Sh NAME 33.Nm gpt 34.Nd GUID partition table maintenance utility 35.Sh SYNOPSIS 36.Nm 37.Op Ar general_options 38.Ar command 39.Op Ar command_options 40.Ar device ... 41.Sh DESCRIPTION 42The 43.Nm 44utility provides the necessary functionality to manipulate GUID partition 45tables (GPTs), but see 46.Sx BUGS 47below for how and where functionality is missing. 48The basic usage model of the 49.Nm 50tool follows that of the 51.Xr cvs 1 52tool. 53The general options are described in the following paragraph. 54The remaining paragraphs describe the individual commands with their options. 55Here we conclude by mentioning that a 56.Ar device 57is either a special file 58corresponding to a disk-like device or a regular file. 59The command is applied to each 60.Ar device 61listed on the command line. 62.Ss General Options 63The general options allow the user to change default settings or otherwise 64change the behaviour that is applicable to all commands. 65Not all commands use all default settings, so some general options may not 66have an effect on all commands. 67.Pp 68The 69.Fl p Ar count 70option allows the user to change the number of partitions the GPT can 71accommodate. 72This is used whenever a new GPT is created. 73By default, the 74.Nm 75utility will create space for 128 partitions (or 32 sectors of 512 bytes). 76.Pp 77The 78.Fl r 79option causes the 80.Nm 81utility to open the device for reading only. 82Currently this option is primarily useful for the 83.Ic show 84command, but the intent 85is to use it to implement dry-run behaviour. 86.Pp 87The 88.Fl v 89option controls the verbosity level. 90The level increases with every occurrence of this option. 91There is no formalized definition of the different levels yet. 92.Ss Commands 93.Bl -tag -width indent 94.\" ==== add ==== 95.It Nm Ic add Oo Fl b Ar number Oc Oo Fl i Ar index Oc Oo Fl s Ar count Oc \ 96Oo Fl t Ar type Oc Ar device ... 97The 98.Ic add 99command allows the user to add a new partition to an existing table. 100By default, it will create a UFS partition covering the first available block 101of an unused disk space. 102The command-specific options can be used to control this behaviour. 103.Pp 104The 105.Fl b Ar number 106option allows the user to specify the starting (beginning) sector number of 107the partition. 108The minimum sector number is 1, but has to fall inside an unused region of 109disk space that is covered by the GPT. 110.Pp 111The 112.Fl i Ar index 113option allows the user to specify which (free) entry in the GPT table is to 114be used for the new partition. 115By default, the first free entry is selected. 116.Pp 117The 118.Fl s Ar count 119option allows the user to specify the size of the partition in sectors. 120The minimum size is 1. 121.Pp 122The 123.Fl t Ar type 124option allows the user to specify the partition type. 125The type is given as an UUID, but 126.Nm 127accepts 128.Cm efi , swap , ufs , hfs , linux , 129and 130.Cm windows 131as aliases for the most commonly used partition types. 132.\" ==== create ==== 133.It Nm Ic create Oo Fl fp Oc Ar device ... 134The 135.Ic create 136command allows the user to create a new (empty) GPT. 137By default, one cannot create a GPT when the device contains a MBR, 138however this can be overridden with the 139.Fl f 140option. 141If the 142.Fl f 143option is specified, an existing MBR is destroyed and any partitions 144described by the MBR are lost. 145.Pp 146The 147.Fl p 148option tells 149.Nm 150to create only the primary table and not the backup table. 151This option is only useful for debugging and should not be used otherwise. 152.\" ==== destroy ==== 153.It Nm Ic destroy Oo Fl r Oc Ar device ... 154The 155.Ic destroy 156command allows the user to destroy an existing, possibly not empty GPT. 157.Pp 158The 159.Fl r 160option instructs 161.Nm 162to destroy the table in a way that it can be recovered. 163.\" ==== label ==== 164.It Nm Ic label Oo Fl a Oc Ao Fl f Ar file | Fl l Ar label Ac Ar device ... 165.It Nm Ic label Oo Fl b Ar number Oc Oo Fl i Ar index Oc \ 166Oo Fl s Ar count Oc Oo Fl t Ar type Oc \ 167Ao Fl f Ar file | Fl l Ar label Ac Ar device ... 168The 169.Ic label 170command allows the user to label any partitions that match the selection. 171At least one of the following selection options must be specified. 172.Pp 173The 174.Fl a 175option specifies that all partitions should be labeled. 176It is mutually exclusive with all other selection options. 177.Pp 178The 179.Fl b Ar number 180option selects the partition that starts at the given block number. 181.Pp 182The 183.Fl i Ar index 184option selects the partition with the given partition number. 185.Pp 186The 187.Fl s Ar count 188option selects all partitions that have the given size. 189This can cause multiple partitions to be removed. 190.Pp 191The 192.Fl t Ar type 193option selects all partitions that have the given type. 194The type is given as an UUID or by the aliases that the 195.Ic add 196command accepts. 197This can cause multiple partitions to be removed. 198.Pp 199The 200.Fl f Ar file 201or 202.Fl l Ar label 203options specify the new label to be assigned to the selected partitions. 204The 205.Fl f Ar file 206option is used to read the label from the specified file. 207Only the first line is read from the file and the trailing newline 208character is stripped. 209If the file name is the dash or minus sign 210.Pq Fl , 211the label is read from 212the standard input. 213The 214.Fl l Ar label 215option is used to specify the label in the command line. 216The label is assumed to be encoded in UTF-8. 217.\" ==== migrate ==== 218.It Nm Ic migrate Oo Fl fs Oc Ar device ... 219The 220.Ic migrate 221command allows the user to migrate an MBR-based disk partitioning into a 222GPT-based partitioning. 223By default, the MBR is not migrated when it contains partitions of an unknown 224type. 225This can be overridden with the 226.Fl f 227option. 228Specifying the 229.Fl f 230option will cause unknown partitions to be ignored and any data in it 231to be lost. 232.Pp 233The 234.Fl s 235option prevents migrating 236.Bx 237disk labels into GPT partitions by creating 238the GPT equivalent of a slice. 239.\" ==== remove ==== 240.It Nm Ic remove Oo Fl a Oc Ar device ... 241.It Nm Ic remove Oo Fl b Ar number Oc Oo Fl i Ar index Oc \ 242Oo Fl s Ar count Oc Oo Fl t Ar type Oc Ar device ... 243The 244.Ic remove 245command allows the user to remove any and all partitions that match the 246selection. 247It uses the same selection options as the 248.Ic label 249command. 250See above for a description of these options. 251Partitions are removed by clearing the partition type. 252No other information is changed. 253.\" ==== show ==== 254.It Nm Ic show Oo Fl lu Oc Ar device ... 255The 256.Ic show 257command displays the current partitioning on the listed devices and gives 258an overall view of the disk contents. 259With the 260.Fl l 261option the GPT partition label will be displayed instead of the GPT partition 262type. 263The option has no effect on non-GPT partitions. 264With the 265.Fl u 266option the GPT partition type is displayed as an UUID instead of in a 267user friendly form. 268The 269.Fl l 270option takes precedence over the 271.Fl u 272option. 273.El 274.Sh SEE ALSO 275.Xr fdisk 8 , 276.Xr mount 8 , 277.Xr newfs 8 , 278.Xr swapon 8 279.Sh HISTORY 280The 281.Nm 282utility appeared in 283.Fx 5.0 284for ia64. 285.Sh BUGS 286The development of the 287.Nm 288utility is still work in progress. 289Many necessary features are missing or partially implemented. 290In practice this means that the manual page, supposed to describe these 291features, is farther removed from being complete or useful. 292As such, missing functionality is not even documented as missing. 293However, it is believed that the currently present functionality is reliable 294and stable enough that this tool can be used without bullet-proof footware if 295one thinks one does not make mistakes. 296.Pp 297It is expected that the basic usage model does not change, but it is 298possible that future versions will not be compatible in the strictest sense 299of the word. 300For example, the 301.Fl p Ar count 302option may be changed to a command option rather than a generic option. 303There are only two commands that use it so there is a chance that the natural 304tendency for people is to use it as a command option. 305Also, options primarily intended for diagnostic or debug purposes may be 306removed in future versions. 307.Pp 308Another possibility is that the current usage model is accompanied by 309other interfaces to make the tool usable as a back-end. 310This all depends on demand and thus feedback. 311