1.\" $NetBSD: gpt.8,v 1.3 2006/11/24 19:46:58 christos 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.Os 31.Dt GPT 8 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 Xo 96.Nm 97.Ic add 98.Op Fl b Ar number 99.Op Fl i Ar index 100.Op Fl s Ar count 101.Op Fl t Ar type 102.Ar device ... 103.Xc 104The 105.Ic add 106command allows the user to add a new partition to an existing table. 107By default, it will create a UFS partition covering the first available block 108of an unused disk space. 109The command-specific options can be used to control this behaviour. 110.Pp 111The 112.Fl b Ar number 113option allows the user to specify the starting (beginning) sector number of 114the partition. 115The minimum sector number is 1, but has to fall inside an unused region of 116disk space that is covered by the GPT. 117.Pp 118The 119.Fl i Ar index 120option allows the user to specify which (free) entry in the GPT table is to 121be used for the new partition. 122By default, the first free entry is selected. 123.Pp 124The 125.Fl s Ar count 126option allows the user to specify the size of the partition in sectors. 127The minimum size is 1. 128.Pp 129The 130.Fl t Ar type 131option allows the user to specify the partition type. 132The type is given as an UUID, but 133.Nm 134accepts 135.Cm efi , swap , ufs , hfs , linux , 136and 137.Cm windows 138as aliases for the most commonly used partition types. 139.\" ==== create ==== 140.It Nm Ic create Oo Fl fp Oc Ar device ... 141The 142.Ic create 143command allows the user to create a new (empty) GPT. 144By default, one cannot create a GPT when the device contains a MBR, 145however this can be overridden with the 146.Fl f 147option. 148If the 149.Fl f 150option is specified, an existing MBR is destroyed and any partitions 151described by the MBR are lost. 152.Pp 153The 154.Fl p 155option tells 156.Nm 157to create only the primary table and not the backup table. 158This option is only useful for debugging and should not be used otherwise. 159.\" ==== destroy ==== 160.It Nm Ic destroy Oo Fl r Oc Ar device ... 161The 162.Ic destroy 163command allows the user to destroy an existing, possibly not empty GPT. 164.Pp 165The 166.Fl r 167option instructs 168.Nm 169to destroy the table in a way that it can be recovered. 170.\" ==== label ==== 171.It Xo 172.Nm 173.Ic label 174.Op Fl a 175.Aq Fl f Ar file | Fl l Ar label 176.Ar device ... 177.Xc 178.It Xo 179.Nm 180.Ic label 181.Op Fl b Ar number 182.Op Fl i Ar index 183.Op Fl s Ar count 184.Op Fl t Ar type 185.Aq Fl f Ar file | Fl l Ar label 186.Ar device ... 187.Xc 188The 189.Ic label 190command allows the user to label any partitions that match the selection. 191At least one of the following selection options must be specified. 192.Pp 193The 194.Fl a 195option specifies that all partitions should be labeled. 196It is mutually exclusive with all other selection options. 197.Pp 198The 199.Fl b Ar number 200option selects the partition that starts at the given block number. 201.Pp 202The 203.Fl i Ar index 204option selects the partition with the given partition number. 205.Pp 206The 207.Fl s Ar count 208option selects all partitions that have the given size. 209This can cause multiple partitions to be removed. 210.Pp 211The 212.Fl t Ar type 213option selects all partitions that have the given type. 214The type is given as an UUID or by the aliases that the 215.Ic add 216command accepts. 217This can cause multiple partitions to be removed. 218.Pp 219The 220.Fl f Ar file 221or 222.Fl l Ar label 223options specify the new label to be assigned to the selected partitions. 224The 225.Fl f Ar file 226option is used to read the label from the specified file. 227Only the first line is read from the file and the trailing newline 228character is stripped. 229If the file name is the dash or minus sign 230.Pq Fl , 231the label is read from 232the standard input. 233The 234.Fl l Ar label 235option is used to specify the label in the command line. 236The label is assumed to be encoded in UTF-8. 237.\" ==== migrate ==== 238.It Nm Ic migrate Oo Fl fs Oc Ar device ... 239The 240.Ic migrate 241command allows the user to migrate an MBR-based disk partitioning into a 242GPT-based partitioning. 243By default, the MBR is not migrated when it contains partitions of an unknown 244type. 245This can be overridden with the 246.Fl f 247option. 248Specifying the 249.Fl f 250option will cause unknown partitions to be ignored and any data in it 251to be lost. 252.Pp 253The 254.Fl s 255option prevents migrating 256.Bx 257disk labels into GPT partitions by creating 258the GPT equivalent of a slice. 259.\" ==== remove ==== 260.It Nm Ic remove Oo Fl a Oc Ar device ... 261.It Xo 262.Nm 263.Ic remove 264.Op Fl b Ar number 265.Op Fl i Ar index 266.Op Fl s Ar count 267.Op Fl t Ar type 268.Ar device ... 269.Xc 270The 271.Ic remove 272command allows the user to remove any and all partitions that match the 273selection. 274It uses the same selection options as the 275.Ic label 276command. 277See above for a description of these options. 278Partitions are removed by clearing the partition type. 279No other information is changed. 280.\" ==== show ==== 281.It Nm Ic show Oo Fl lu Oc Ar device ... 282The 283.Ic show 284command displays the current partitioning on the listed devices and gives 285an overall view of the disk contents. 286With the 287.Fl l 288option the GPT partition label will be displayed instead of the GPT partition 289type. 290The option has no effect on non-GPT partitions. 291With the 292.Fl u 293option the GPT partition type is displayed as an UUID instead of in a 294user friendly form. 295The 296.Fl l 297option takes precedence over the 298.Fl u 299option. 300.El 301.Sh SEE ALSO 302.Xr fdisk 8 , 303.Xr mount 8 , 304.Xr newfs 8 , 305.Xr swapon 8 306.Sh HISTORY 307The 308.Nm 309utility appeared in 310.Fx 5.0 311for ia64. 312.Sh BUGS 313The development of the 314.Nm 315utility is still work in progress. 316Many necessary features are missing or partially implemented. 317In practice this means that the manual page, supposed to describe these 318features, is farther removed from being complete or useful. 319As such, missing functionality is not even documented as missing. 320However, it is believed that the currently present functionality is reliable 321and stable enough that this tool can be used without bullet-proof footware if 322one thinks one does not make mistakes. 323.Pp 324It is expected that the basic usage model does not change, but it is 325possible that future versions will not be compatible in the strictest sense 326of the word. 327For example, the 328.Fl p Ar count 329option may be changed to a command option rather than a generic option. 330There are only two commands that use it so there is a chance that the natural 331tendency for people is to use it as a command option. 332Also, options primarily intended for diagnostic or debug purposes may be 333removed in future versions. 334.Pp 335Another possibility is that the current usage model is accompanied by 336other interfaces to make the tool usable as a back-end. 337This all depends on demand and thus feedback. 338