NAME | SYNOPSIS | DESCRIPTION | COMMANDS | OPTIONS | INPUT FORMATS | EMPTY DISK LABEL | BACKING UP THE PARTITION TABLE | COLORS | NOTES | ENVIRONMENT | SEE ALSO | AUTHOR | AVAILABILITY | COLOPHON

SFDISK(8)                   System Administration                  SFDISK(8)

NAME         top

       sfdisk - display or manipulate a disk partition table

SYNOPSIS         top

       sfdisk [options] device [-N partition-number]

       sfdisk [options] command

DESCRIPTION         top

       sfdisk is a script-oriented tool for partitioning any block device.

       Since version 2.26 sfdisk supports MBR (DOS), GPT, SUN and SGI disk
       labels, but no longer provides any functionality for CHS (Cylinder-
       Head-Sector) addressing.  CHS has never been important for Linux, and
       this addressing concept does not make any sense for new devices.

       sfdisk (since version 2.26) aligns the start and end of partitions to
       block-device I/O limits when relative sizes are specified, when the
       default values are used or when multiplicative suffixes (e.g MiB) are
       used for sizes.  It is possible that partition size will be optimized
       (reduced or enlarged) due to alignment if the start offset is
       specified exactly in sectors and partition size relative or by
       multiplicative suffixes.

       The recommended way is not to specify start offsets at all and
       specify partition size in MiB, GiB (or so).  In this case sfdisk
       align all partitions to block-device I/O limits (or when I/O limits
       are too small then to megabyte boundary to keep disk layout
       portable).  If this default behaviour is unwanted (usually for very
       small partitions) then specify offsets and sizes in sectors.  In this
       case sfdisk entirely follows specified numbers without any
       optimization.

       sfdisk does not create the standard system partitions for SGI and SUN
       disk labels like fdisk(8) does.  It is necessary to explicitly create
       all partitions including whole-disk system partitions.

COMMANDS         top

       The commands are mutually exclusive.

       [-N partition-number] device
              The default sfdisk command is to read the specification for
              the desired partitioning of device from standard input, and
              then create a partition table according to the specification.
              See below for the description of the input format.  If
              standard input is a terminal, then sfdisk starts an
              interactive session.

              If the option -N is specified, then the changes are applied to
              the partition addressed by partition-number.  The unspecified
              fields of the partition are not modified.

              Note that it's possible to address an unused partition with
              -N.  For example, an MBR always contains 4 partitions, but the
              number of used partitions may be smaller.  In this case sfdisk
              follows the default values from the partition table and does
              not use built-in defaults for the unused partition given with
              -N.  See also --append.

       -A, --activate device [partition-number...]
              Switch on the bootable flag for the specified partitions.  If
              no partition-number is specified, then list the partitions
              with an enabled flag.

       --delete device [partition-number...]
              Delete all or the specified partitions.

       -d, --dump device
              Dump the partitions of a device in a format that is usable as
              input to sfdisk.  See the section BACKING UP THE PARTITION
              TABLE.

       -g, --show-geometry [device...]
              List the geometry of all or the specified devices. For
              backward compatibility the deprecated option
              --show-pt-geometry have the same meaning as this one.

       -J, --json device
              Dump the partitions of a device in JSON format.  Note that
              sfdisk is not able to use JSON as input format.

       -l, --list [device...]
              List the partitions of all or the specified devices.  This
              command can be used together with --verify.

       -F, --list-free [device...]
              List the free unpartitioned areas on all or the specified
              devices.

       --part-attrs device partition-number [attributes]
              Change the GPT partition attribute bits.  If attributes is not
              specified, then print the current partition settings.  The
              attributes argument is a comma- or space-delimited list of
              bits.  The currently supported attribute bits are:
              RequiredPartition, NoBlockIOProtocol, LegacyBIOSBootable and
              GUID-specific bits in the range from 48 to 63.  For example,
              the string "RequiredPartition,50,51" sets three bits.

       --part-label device partition-number [label]
              Change the GPT partition name (label).  If label is not
              specified, then print the current partition label.

       --part-type device partition-number [type]
              Change the partition type.  If type is not specified, then
              print the current partition type.  The type argument is
              hexadecimal for MBR, or a GUID for GPT.  For backward
              compatibility the options -c and --id have the same meaning as
              this one.

       --part-uuid device partition-number [uuid]
              Change the GPT partition UUID.  If uuid is not specified, then
              print the current partition UUID.

       -r, --reorder device
              Renumber the partitions, ordering them by their start offset.

       -s, --show-size [device...]
              List the sizes of all or the specified devices.

       -T, --list-types
              Print all supported types for the current disk label or the
              label specified by --label.

       -V, --verify [device...]
              Test whether the partition table and partitions seem correct.

OPTIONS         top

       -a, --append
              Don't create a new partition table, but only append the
              specified partitions.

       -b, --backup
              Back up the current partition table sectors before starting
              the partitioning.  The default backup file name is
              ~/sfdisk-<device>-<offset>.bak; to use another name see option
              -O, --backup-file.

       --color[=when]
              Colorize the output.  The optional argument when can be auto,
              never or always.  If the when argument is omitted, it defaults
              to auto.  The colors can be disabled; for the current built-in
              default see the --help output.  See also the COLORS section.

       -f, --force
              Disable all consistency checking.

       --Linux
              Deprecated and ignored option.  Partitioning that is
              compatible with Linux (and other modern operating systems) is
              the default.

       -n, --no-act
              Do everything except writing to the device.

       --no-reread
              Do not check through the re-read-partition-table ioctl whether
              the device is in use.

       --no-tell-kernel
              Don't tell the kernel about partition changes. This option is
              recommended together with --no-reread to modify a partition on
              used disk. The modified partition should not be used (e.g.
              mounted).

       -O, --backup-file path
              Override the default backup file name.  Note that the device
              name and offset are always appended to the file name.

       --move-data[=path]
              Move data after partition relocation, for example when moving
              the beginning of a partition to another place on the disk.
              The size of the partition has to remain the same, the new and
              old location may overlap.  This option requires option -N in
              order to be processed on one specific partition only.

              The path overrides the default log file name (the default is
              ~/sfdisk-<devname>.move).  The log file contains information
              about all read/write operations on the partition data.

              Note that this operation is risky and not atomic. Don't forget
              to backup your data!

              In the example below, the first command creates a 100MiB free
              area before the first partition and moves the data it contains
              (e.g. a filesystem), the next command creates a new partition
              from the free space (at offset 2048), and the last command
              reorders partitions to match disk order (the original sdc1
              will become sdc2).

              echo '+100M,' | sfdisk --move-data /dev/sdc -N 1
              echo '2048,' | sfdisk /dev/sdc --append
              sfdisk /dev/sdc --reorder

       -o, --output list
              Specify which output columns to print.  Use --help to get a
              list of all supported columns.

              The default list of columns may be extended if list is
              specified in the format +list (e.g. -o +UUID).

       -q, --quiet
              Suppress extra info messages.

       -u, --unit S
              Deprecated option.  Only the sector unit is supported.

       -X, --label type
              Specify the disk label type (e.g. dos, gpt, ...).  If this
              option is not given, then sfdisk defaults to the existing
              label, but if there is no label on the device yet, then the
              type defaults to dos. The default or the current label may be
              overwritten by the "label: <name>" script header line. The
              option --label does not force sfdisk to create empty disk
              label (see the EMPTY DISK LABEL section below).

       -Y, --label-nested type
              Force editing of a nested disk label.  The primary disk label
              has to exist already.  This option allows to edit for example
              a hybrid/protective MBR on devices with GPT.

       -w, --wipe when
              Wipe filesystem, RAID and partition-table signatures from the
              device, in order to avoid possible collisions.  The argument
              when can be auto, never or always.  When this option is not
              given, the default is auto, in which case signatures are wiped
              only when in interactive mode; except the old partition-table
              signatures which are always wiped before create a new
              partition-table if the argument when is not never. In all
              cases detected signatures are reported by warning messages
              before a new partition table is created.  See also wipefs(8)
              command.

       -W, --wipe-partitions when
              Wipe filesystem, RAID and partition-table signatures from a
              newly created partitions, in order to avoid possible
              collisions.  The argument when can be auto, never or always.
              When this option is not given, the default is auto, in which
              case signatures are wiped only when in interactive mode and
              after confirmation by user.  In all cases detected signatures
              are reported by warning messages after a new partition is
              created.  See also wipefs(8) command.

       -v, --version
              Display version information and exit.

       -h, --help
              Display help text and exit.

INPUT FORMATS         top

       sfdisk supports two input formats and generic header lines.

       Header lines
              The optional header lines specify generic information that
              apply to the partition table.  The header-line format is:

                     <name>: <value>

              The currently recognized headers are:

                     unit   Specify the partitioning unit.  The only
                            supported unit is sectors.

                     label  Specify the partition table type.  For example
                            dos or gpt.

                     label-id
                            Specify the partition table identifier.  It
                            should be a  hexadecimal number (with a 0x
                            prefix) for MBR and a UUID for GPT.

              Note that it is only possible to use header lines before the
              first partition is specified in the input.

       Unnamed-fields format

                     start size type bootable

              where each line fills one partition descriptor.

              Fields are separated by whitespace, comma or semicolon
              possibly followed by whitespace; initial and trailing
              whitespace is ignored.  Numbers can be octal, decimal or
              hexadecimal; decimal is the default.  When a field is absent,
              empty or specified as '-' a default value is used.  But when
              the -N option (change a single partition) is given, the
              default for each field is its previous value.

              The default value of start is the first non-assigned sector
              aligned according to device I/O limits.  The default start
              offset for the first partition is 1 MiB.  The offset may be
              followed by the multiplicative suffixes (KiB, MiB, GiB, TiB,
              PiB, EiB, ZiB and YiB) then the number is interpreted as
              offset in bytes.

              The default value of size indicates "as much as possible";
              i.e. until the next partition or end-of-device.  A numerical
              argument is by default interpreted as a number of sectors,
              however if the size is followed by one of the multiplicative
              suffixes (KiB, MiB, GiB, TiB, PiB, EiB, ZiB and YiB) then the
              number is interpreted as the size of the partition in bytes
              and it is then aligned according to the device I/O limits.  A
              '+' can be used instead of a number to enlarge the partition
              as much as possible.  Note '+' is equivalent to the default
              behaviour for a new partition; existing partitions will be
              resized as required.

              The partition type is given in hex for MBR (DOS), without the
              0x prefix, a GUID string for GPT, or a shortcut:

                     L      Linux; means 83 for MBR and
                            0FC63DAF-8483-4772-8E79-3D69D8477DE4 for GPT.

                     S      swap area; means 82 for MBR and 0657FD6D-
                            A4AB-43C4-84E5-0933C84B4F4F for GPT

                     E      extended partition; means 5 for MBR

                     H      home partition; means
                            933AC7E1-2EB4-4F13-B844-0E14E2AEF915 for GPT

                     X      linux extended partition; means 85 for MBR.

                     U      EFI System partition, means EF for MBR and
                            C12A7328-F81F-11D2-BA4B-00A0C93EC93B for GPT

              The default type value is L

              bootable is specified as [*|-], with as default not-bootable.
              The value of this field is irrelevant for Linux - when Linux
              runs it has been booted already - but ir might play a role for
              certain boot loaders and for other operating systems.

       Named-fields format
              This format is more readable, robust, extensible and allows to
              specify additional information (e.g. a UUID).  It is
              recommended to use this format to keep your scripts more
              readable.

                     [device :] name[=value], ...

              The device field is optional.  sfdisk extracts the partition
              number from the device name.  It allows to specify the
              partitions in random order.  This functionality is mostly used
              by --dump.  Don't use it if you are not sure.

              The value can be between quotation marks (e.g. name="This is
              partition name").  The currently supported fields are:

                     start=number
                            The first non-assigned sector aligned according
                            to device I/O limits.  The default start offset
                            for the first partition is 1 MiB. The offset may
                            be followed by the multiplicative suffixes (KiB,
                            MiB, GiB, TiB, PiB, EiB, ZiB and YiB) then the
                            number is interpreted as offset in bytes.

                     size=number
                            Specify the partition size in sectors.  The
                            number may be followed by the multiplicative
                            suffixes (KiB, MiB, GiB, TiB, PiB, EiB, ZiB and
                            YiB), then it's interpreted as size in bytes and
                            the size is aligned according to device I/O
                            limits.

                     bootable
                            Mark the partition as bootable.

                     attrs=string
                            Partition attributes, usually GPT partition
                            attribute bits.  See --part-attrs for more
                            details about the GPT-bits string format.

                     uuid=string
                            GPT partition UUID.

                     name=string
                            GPT partition name.

                     type=code
                            A hexadecimal number (without 0x) for an MBR
                            partition, or a GUID for a GPT partition.  For
                            backward compatibility the Id= field has the
                            same meaning.

EMPTY DISK LABEL         top

       sfdisk does not create partition table without partitions by default.
       The lines with partitions are expected in the script by default. The
       empty partition table has to be explicitly requested by "label:
       <name>" script header line without any partitions lines. For example:

              echo 'label: gpt' | sfdisk /dev/sdb

       creates empty GPT partition table. Note that the --append disables
       this feature.

BACKING UP THE PARTITION TABLE         top

       It is recommended to save the layout of your devices.  sfdisk
       supports two ways.

       Use the --dump option to save a description of the device layout to a
       text file.  The dump format is suitable for later sfdisk input.  For
       example:

              sfdisk --dump /dev/sda > sda.dump

       This can later be restored by:

              sfdisk /dev/sda < sda.dump

       If you want to do a full (binary) backup of all sectors where the
       partition table is stored, then use the --backup option.  It writes
       the sectors to ~/sfdisk-<device>-<offset>.bak files.  The default
       name of the backup file can be changed with the --backup-file option.
       The backup files contain only raw data from the device.  Note that
       the same concept of backup files is used by wipefs(8).  For example:

              sfdisk --backup /dev/sda

       The GPT header can later be restored by:

              dd  if=~/sfdisk-sda-0x00000200.bak  of=/dev/sda  \
                seek=$((0x00000200))  bs=1  conv=notrunc

       Note that sfdisk since version 2.26 no longer provides the -I option
       to restore sectors.  dd(1) provides all necessary functionality.

COLORS         top

       Implicit coloring can be disabled by an empty file /etc/terminal-
       colors.d/sfdisk.disable.

       See terminal-colors.d(5) for more details about colorization
       configuration. The logical color names supported by sfdisk are:

       header The header of the output tables.

       warn   The warning messages.

       welcome
              The welcome message.

NOTES         top

       Since version 2.26 sfdisk no longer provides the -R or --re-read
       option to force the kernel to reread the partition table.  Use
       blockdev --rereadpt instead.

       Since version 2.26 sfdisk does not provide the --DOS, --IBM,
       --DOS-extended, --unhide, --show-extended, --cylinders, --heads,
       --sectors, --inside-outer, --not-inside-outer options.

ENVIRONMENT         top

       SFDISK_DEBUG=all
              enables sfdisk debug output.

       LIBFDISK_DEBUG=all
              enables libfdisk debug output.

       LIBBLKID_DEBUG=all
              enables libblkid debug output.

       LIBSMARTCOLS_DEBUG=all
              enables libsmartcols debug output.

SEE ALSO         top

       fdisk(8), cfdisk(8), parted(8), partprobe(8), partx(8)

AUTHOR         top

       Karel Zak <kzak@redhat.com>

       The current sfdisk implementation is based on the original sfdisk
       from Andries E. Brouwer.

AVAILABILITY         top

       The sfdisk command is part of the util-linux package and is available
       from https://www.kernel.org/pub/linux/utils/util-linux/.

COLOPHON         top

       This page is part of the util-linux (a random collection of Linux
       utilities) project.  Information about the project can be found at 
       ⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩.  If you have a
       bug report for this manual page, send it to
       util-linux@vger.kernel.org.  This page was obtained from the
       project's upstream Git repository 
       ⟨git://git.kernel.org/pub/scm/utils/util-linux/util-linux.git⟩ on
       2017-05-03.  If you discover any rendering problems in this HTML ver‐
       sion of the page, or you believe there is a better or more up-to-date
       source for the page, or you have corrections or improvements to the
       information in this COLOPHON (which is not part of the original man‐
       ual page), send a mail to man-pages@man7.org

util-linux                        June 2015                        SFDISK(8)

Pages that refer to this page: cfdisk(8)fdisk(8)