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SFDISK(8)                             System Administration                             SFDISK(8)

NAME
       sfdisk - display or manipulate a disk partition table

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

       sfdisk [options] command

DESCRIPTION
       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, or when the default values are used.

       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
       The commands are mutually exclusive.

       [-N partition-number] device
              The default sfdisk command is to read the specification for the desired  partition‐
              ing  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.  If no partition-number is specified, then all parti‐
              tions with an enabled flag are listed.

       -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.

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

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

       --part-type device partno [type]
              Change the partition type.  If type is not specified, then print the current parti‐
              tion type.  The type argument is hexadecimal for MBR, or a GUID for GPT.  For back‐
              ward compatibility the options -c and --id have the same meaning.

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

       -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
       -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--.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.

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

       -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.

       -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.

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

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

INPUT FORMATS
       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:

                     : 

              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 white‐
              space; 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 par‐
              tition  or end-of-device.  A numerical argument is by default interpreted as a num‐
              ber of sectors, however if the size is followed by one of the  multiplicative  suf‐
              fixes (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.

              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, extendible 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.  sfdiskextracts 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.

BACKING UP THE PARTITION TABLE
       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--.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 con‐
       cept 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
       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
       Since  version 2.26 sfdisk no longer provides the -R or --re-read option to force the ker‐
       nel 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
       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
       fdisk(8), cfdisk(8), parted(8), partprobe(8), partx(8)

AUTHOR
       Karel Zak 

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

AVAILABILITY
       The sfdisk command is part of the util-linux package and is available from  ftp://ftp.ker‐
       nel.org/pub/linux/utils/util-linux/.

util-linux                                  June 2015                                   SFDISK(8)

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