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  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.  If no partition-number is speci-
              fied, then all partitions 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 TA-
              BLE.

       -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 com-
              mand 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 speci-
              fied, then print the  current  partition  settings.   The  attrs
              argument  is a comma- or space-delimited list of bits.  The cur-
              rently supported attribute bits are: RequiredPartiton,  NoBlock-
              IOProtocol,  LegacyBIOSBootable  and  GUID-specific  bits in the
              range from 48 to 63.  For example,  the  string  "RequiredParti-
              ton,50,51" sets three bits.

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

       --part-type device partno [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.

       --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 speci-
              fied 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.

       -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:

                     <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 off-
              set 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  inter-
              preted  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 possi-
              ble.  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 num-
              ber  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 par-
                            tition, or a GUID for a GPT partition.  For  back-
                            ward  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 par-
       tition 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
       Implicit coloring can be disabled by an empty  file  /etc/terminal-col-
       ors.d/sfdisk.disable.

       See terminal-colors.d(5) for more details about colorization configura-
       tion. 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  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, --sec-
       tors, --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 <kzak@redhat.com>

       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.kernel.org/pub/linux/utils/util-linux/.

util-linux                         June 2015                         SFDISK(8)