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 1.2 2007/06/17 08:15:08 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 , dfly ,
137 as aliases for the most commonly used partition types.
138 You may also specify any symbolic name in the system uuids file.
140 .It Nm Ic create Oo Fl fp Oc Ar device ...
143 command allows the user to create a new (empty) GPT.
144 By default, one cannot create a GPT when the device contains a MBR,
145 however this can be overridden with the
150 option is specified, an existing MBR is destroyed and any partitions
151 described by the MBR are lost.
157 to create only the primary table and not the backup table.
158 This 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 ...
163 command allows the user to destroy an existing, possibly not empty GPT.
169 to destroy the table in a way that it can be recovered.
175 .Aq Fl f Ar file | Fl l Ar label
185 .Aq Fl f Ar file | Fl l Ar label
190 command allows the user to label any partitions that match the selection.
191 At least one of the following selection options must be specified.
195 option specifies that all partitions should be labeled.
196 It is mutually exclusive with all other selection options.
200 option selects the partition that starts at the given block number.
204 option selects the partition with the given partition number.
208 option selects all partitions that have the given size.
209 This can cause multiple partitions to be removed.
213 option selects all partitions that have the given type.
214 The type is given as an UUID or by the aliases that the
217 This can cause multiple partitions to be removed.
223 options specify the new label to be assigned to the selected partitions.
226 option is used to read the label from the specified file.
227 Only the first line is read from the file and the trailing newline
228 character is stripped.
229 If the file name is the dash or minus sign
231 the label is read from
235 option is used to specify the label in the command line.
236 The label is assumed to be encoded in UTF-8.
237 .\" ==== migrate ====
238 .It Nm Ic migrate Oo Fl fs Oc Ar device ...
241 command allows the user to migrate an MBR-based disk partitioning into a
242 GPT-based partitioning.
243 By default, the MBR is not migrated when it contains partitions of an unknown
245 This can be overridden with the
250 option will cause unknown partitions to be ignored and any data in it
255 option prevents migrating
257 disk labels into GPT partitions by creating
258 the GPT equivalent of a slice.
260 .It Nm Ic remove Oo Fl a Oc Ar device ...
272 command allows the user to remove any and all partitions that match the
274 It uses the same selection options as the
277 See above for a description of these options.
278 Partitions are removed by clearing the partition type.
279 No other information is changed.
281 .It Nm Ic show Oo Fl lu Oc Ar device ...
284 command displays the current partitioning on the listed devices and gives
285 an overall view of the disk contents.
288 option the GPT partition label will be displayed instead of the GPT partition
290 The option has no effect on non-GPT partitions.
293 option the GPT partition type is displayed as an UUID instead of in a
297 option takes precedence over the
313 The development of the
315 utility is still work in progress.
316 Many necessary features are missing or partially implemented.
317 In practice this means that the manual page, supposed to describe these
318 features, is farther removed from being complete or useful.
319 As such, missing functionality is not even documented as missing.
320 However, it is believed that the currently present functionality is reliable
321 and stable enough that this tool can be used without bullet-proof footware if
322 one thinks one does not make mistakes.
324 It is expected that the basic usage model does not change, but it is
325 possible that future versions will not be compatible in the strictest sense
329 option may be changed to a command option rather than a generic option.
330 There are only two commands that use it so there is a chance that the natural
331 tendency for people is to use it as a command option.
332 Also, options primarily intended for diagnostic or debug purposes may be
333 removed in future versions.
335 Another possibility is that the current usage model is accompanied by
336 other interfaces to make the tool usable as a back-end.
337 This all depends on demand and thus feedback.