FreeBSD Man Pages

gpt(8)

NAME

     gpt -- GUID partition table maintenance utility

SYNOPSIS

     gpt [general_options] command [command_options] device ...

DESCRIPTION

     The gpt utility provides the necessary functionality to manipulate GUID
     partition tables (GPTs), but see BUGS below for how and where functional-
     ity is missing.  The basic usage model of the gpt tool follows that of
     the cvs(1) tool.  The general options are described in the following
     paragraph.  The remaining paragraphs describe the individual commands
     with their options.  Here we conclude by mentioning that a device is
     either a special file corresponding to a disk-like device or a regular
     file.  The command is applied to each device listed on the command line.

   General Options
     The general options allow the user to change default settings or other-
     wise change the behaviour that is applicable to all commands.  Not all
     commands use all default settings, so some general options may not have
     an effect on all commands.

     The -p count option allows the user to change the number of partitions
     the GPT can accomodate.  This is used whenever a new GPT is created.  By
     default, the gpt utility will create space for 128 partitions (or 32 sec-
     tors of 512 bytes).

     The -r option causes the gpt utility to open the device for reading only.
     Currently this option is primarily useful for the show command, but the
     intent is to use it to implement dry-run behaviour.

     The -v option controls the verbosity level.  The level increases with
     every occurrence of this option.  There is no formalized definition of
     the different levels yet.

   Commands
     gpt add [-b number] [-i index] [-s count] [-t type] device ...
	     The add command allows the user to add a new partition to an
	     existing table.  By default, it will create a UFS partition cov-
	     ering the first available block of an unused disk space.  The
	     command-specific options can be used to control this behaviour.

	     The -b number option allows the user to specify the starting
	     (beginning) sector number of the partition.  The minimum sector
	     number is 1, but has to fall inside an unused region of disk
	     space that is covered by the GPT.

	     The -i index option allows the user to specify which (free) entry
	     in the GPT table is to be used for the new partition.  By
	     default, the first free entry is selected.

	     The -s count option allows the user to specify the size of the
	     partition in sectors.  The minimum size is 1.

	     The -t type option allows the user to specify the partition type.
	     The type is given as an UUID, but gpt accepts efi, swap, ufs,
	     linux and windows as aliases for the most commonly used partition

	     The -p option tells gpt to create only the primary table and not
	     the backup table.	This option is only useful for debugging and
	     should not be used otherwise.

     gpt destroy [-r] device ...
	     The destroy command allows the user to destroy an existing, pos-
	     sibly not empty GPT.

	     The -r option instructs gpt to destroy the table in a way that it
	     can be recovered.

     gpt migrate [-fs] device ...
	     The migrate command allows the user to migrate an MBR-based disk
	     partitioning into a GPT-based partitioning.  By default, the MBR
	     is not migrated when it contains partitions of an unknown type.
	     This can be overridden with the -f option.  Specifying the -f
	     option will cause unknown partitions to be ignored and any data
	     in it to be lost.

	     The -s option prevents migrating BSD disk labels into GPT parti-
	     tions by creating the GPT equivalent of a slice.

     gpt remove [-b number] [-i index] [-s count] [-t type] device ...
	     The remove command allows the user to remove any partitions that
	     match the selection.  BEWARE: when no options are given, all GPT
	     partitions will match and thus will be deleted.

	     The -b number option selects the partitions that starts at the
	     given number.

	     The -i index option selects the partition with the given parti-
	     tion number.

	     The -s count option selects all partitions that have the given
	     size.  This can cause multiple partitions to be removed.

	     The -t type option selects all partitions that have the given
	     type.  The type is given as an UUID or by the aliases that the
	     add command accepts.  This can cause multiple partitions to be
	     removed.

     gpt show device ...
	     The show command displays the current partitioning on the listed
	     devices and gives an overall view of the disk contents.

SEE ALSO

     fdisk(8), mount(8), newfs(8), swapon(8)

HISTORY

     The gpt utility appeared in FreeBSD 5.0 for ia64.

BUGS

     The development of the gpt utility is still work in progress.  Many nec-
     essary features are missing or partially implemented.  In practice this
     means that the manual page, supposed to describe these features, is far-
     ther removed from being complete or useful.  As such, missing functional-
     ity is not even documented as missing.  However, it is believed that the
     that use it so there is a chance that the natural tendency for people is
     to use it as a command option.  Also, options primarily intended for
     diagnostic or debug purposes may be removed in future versions.

     Another possibility is that the current usage model is accompanied by
     other interfaces to make the tool usable as a back-end.  This all depends
     on demand and thus feedback.

FreeBSD 5.4		       November 12, 2004		   FreeBSD 5.4

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