1 .\" Copyright (c) 2002 Marcel Moolenaar
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25 .\" $FreeBSD: src/sbin/gpt/gpt.8,v 1.17 2006/06/22 22:22:32 marcel Exp $
26 .\" $DragonFly: src/sbin/gpt/gpt.8,v 1.1 2007/06/16 22:29:27 dillon Exp $
33 .Nd "GUID partition table maintenance utility"
36 .Op Ar general_options
38 .Op Ar command_options
43 utility provides the necessary functionality to manipulate GUID partition
44 tables (GPTs), but see
46 below for how and where functionality is missing.
47 The basic usage model of the
49 tool follows that of the
52 The general options are described in the following paragraph.
53 The remaining paragraphs describe the individual commands with their options.
54 Here we conclude by mentioning that a
56 is either a special file
57 corresponding to a disk-like device or a regular file.
58 The command is applied to each
60 listed on the command line.
62 The general options allow the user to change default settings or otherwise
63 change the behaviour that is applicable to all commands.
64 Not all commands use all default settings, so some general options may not
65 have an effect on all commands.
69 option allows the user to change the number of partitions the GPT can
71 This is used whenever a new GPT is created.
74 utility will create space for 128 partitions (or 32 sectors of 512 bytes).
80 utility to open the device for reading only.
81 Currently this option is primarily useful for the
83 command, but the intent
84 is to use it to implement dry-run behaviour.
88 option controls the verbosity level.
89 The level increases with every occurrence of this option.
90 There is no formalized definition of the different levels yet.
92 .Bl -tag -width indent
105 command allows the user to add a new partition to an existing table.
106 By default, it will create a UFS partition covering the first available block
107 of an unused disk space.
108 The command-specific options can be used to control this behaviour.
112 option allows the user to specify the starting (beginning) sector number of
114 The minimum sector number is 1, but has to fall inside an unused region of
115 disk space that is covered by the GPT.
119 option allows the user to specify which (free) entry in the GPT table is to
120 be used for the new partition.
121 By default, the first free entry is selected.
125 option allows the user to specify the size of the partition in sectors.
126 The minimum size is 1.
130 option allows the user to specify the partition type.
131 The type is given as an UUID, but
134 .Cm efi , swap , ufs , hfs , linux
137 as aliases for the most commonly used partition types.
139 .It Nm Ic create Oo Fl fp Oc Ar device ...
142 command allows the user to create a new (empty) GPT.
143 By default, one cannot create a GPT when the device contains a MBR,
144 however this can be overridden with the
149 option is specified, an existing MBR is destroyed and any partitions
150 described by the MBR are lost.
156 to create only the primary table and not the backup table.
157 This option is only useful for debugging and should not be used otherwise.
158 .\" ==== destroy ====
159 .It Nm Ic destroy Oo Fl r Oc Ar device ...
162 command allows the user to destroy an existing, possibly not empty GPT.
168 to destroy the table in a way that it can be recovered.
174 .Aq Fl f Ar file | Fl l Ar label
184 .Aq Fl f Ar file | Fl l Ar label
189 command allows the user to label any partitions that match the selection.
190 At least one of the following selection options must be specified.
194 option specifies that all partitions should be labeled.
195 It is mutually exclusive with all other selection options.
199 option selects the partition that starts at the given block number.
203 option selects the partition with the given partition number.
207 option selects all partitions that have the given size.
208 This can cause multiple partitions to be removed.
212 option selects all partitions that have the given type.
213 The type is given as an UUID or by the aliases that the
216 This can cause multiple partitions to be removed.
222 options specify the new label to be assigned to the selected partitions.
225 option is used to read the label from the specified file.
226 Only the first line is read from the file and the trailing newline
227 character is stripped.
228 If the file name is the dash or minus sign
230 the label is read from
234 option is used to specify the label in the command line.
235 The label is assumed to be encoded in UTF-8.
236 .\" ==== migrate ====
237 .It Nm Ic migrate Oo Fl fs Oc Ar device ...
240 command allows the user to migrate an MBR-based disk partitioning into a
241 GPT-based partitioning.
242 By default, the MBR is not migrated when it contains partitions of an unknown
244 This can be overridden with the
249 option will cause unknown partitions to be ignored and any data in it
254 option prevents migrating
256 disk labels into GPT partitions by creating
257 the GPT equivalent of a slice.
259 .It Nm Ic remove Oo Fl a Oc Ar device ...
271 command allows the user to remove any and all partitions that match the
273 It uses the same selection options as the
276 See above for a description of these options.
277 Partitions are removed by clearing the partition type.
278 No other information is changed.
280 .It Nm Ic show Oo Fl lu Oc Ar device ...
283 command displays the current partitioning on the listed devices and gives
284 an overall view of the disk contents.
287 option the GPT partition label will be displayed instead of the GPT partition
289 The option has no effect on non-GPT partitions.
292 option the GPT partition type is displayed as an UUID instead of in a
296 option takes precedence over the
312 The development of the
314 utility is still work in progress.
315 Many necessary features are missing or partially implemented.
316 In practice this means that the manual page, supposed to describe these
317 features, is farther removed from being complete or useful.
318 As such, missing functionality is not even documented as missing.
319 However, it is believed that the currently present functionality is reliable
320 and stable enough that this tool can be used without bullet-proof footware if
321 one thinks one does not make mistakes.
323 It is expected that the basic usage model does not change, but it is
324 possible that future versions will not be compatible in the strictest sense
328 option may be changed to a command option rather than a generic option.
329 There are only two commands that use it so there is a chance that the natural
330 tendency for people is to use it as a command option.
331 Also, options primarily intended for diagnostic or debug purposes may be
332 removed in future versions.
334 Another possibility is that the current usage model is accompanied by
335 other interfaces to make the tool usable as a back-end.
336 This all depends on demand and thus feedback.