SFDISK(8)                    System Administration                   SFDISK(8)

       sfdisk - display or manipulate a disk partition table

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

       sfdisk [options] command

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

       Since version 2.26 sfdisk supports MBR (DOS), GPT, SUN and SGI disk la-
       bels, 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 de-
       fault 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

       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 par-
       titions 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 de-
       fault 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.

       sfdisk uses BLKRRPART (reread partition table) ioctl to make sure  that
       the  device  is  not  used  by  system or another tools (see also --no-
       reread).  It's possible that this feature or  another  sfdisk  activity
       races with udevd.  The recommended way how to avoid possible collisions
       is to use exclusive flock for the whole-disk device to serialize device
       access.  The exclusive lock will cause udevd to skip the event handling
       on the device.  For example:

              flock /dev/sdc sfdisk /dev/sdc

       Note, this semantic is not currently supported by udevd for MD  and  DM

       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  in-
              put 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  and
              switch  off the bootable flag on all unspecified partitions. The
              special placeholder '-' may be used  instead  of  the  partition
              numbers to switch off the bootable flag on all partitions.

              The  activation  command is supported for MBR and PMBR only.  If
              GPT label is detected than sfdisk prints warning  and  automati-
              cally enter PMBR.

              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 TA-

       -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 com-
              mand can be used together with --verify.

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

       --part-attrs device partition-number [attributes]
              Change  the  GPT partition attribute bits.  If attributes is not
              specified, then print the current partition settings.   The  at-
              tributes  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  "RequiredPar-
              tition,50,51" sets three bits.

       --part-label device partition-number [label]
              Change  the  GPT partition name (label).  If label is not speci-
              fied, 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  op-
              tions -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 in units of  1024
              byte size.  This command is DEPRECATED in favour of blockdev(1).

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

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

       -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-<de-
              vice>-<offset>.bak;   to   use   another  name  see  option  -O,

              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.

              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.

              Do not check through the re-read-partition-table  ioctl  whether
              the device is in use.

              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.

       -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  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 re-
              orders 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. This op-
              tion is not supported when using the --show-size command.

       -X, --label type
              Specify the disk label type (e.g. dos, gpt, ...).  If  this  op-
              tion  is  not given, then sfdisk defaults to the existing label,
              but if there is no label on the device yet, then  the  type  de-
              faults to dos. The default or the current label may be overwrit-
              ten by the "label: <name>" script header line. The option  --la-
              bel  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 parti-
              tion 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  op-
              tion 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 warn-
              ing 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.

       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.

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

                            Specify the first usable  sector  for  GPT  parti-

                            Specify the last usable sector for GPT partitions.

                            Specify the maximal number of GPT partitions.

                     grain  Specify  minimal  size  in bytes used to calculate
                            partitions alignment.  The  default  is  1MiB  and
                            it's  strongly recommended to use the default.  Do
                            not modify this variable if you're not sure.

              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  ig-
              nored.  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 sin-
              gle partition) is given, the default for each field is its  pre-
              vious 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 fol-
              lowed by the multiplicative suffixes (KiB, MiB, GiB,  TiB,  PiB,
              EiB,  ZiB  and  YiB) then the number is interpreted as offset in

              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.

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

                     R      Linux    RAID;    means    FD    for    MBR    and
                            A19D880F-05FC-4D3B-A006-743F0F84911E for GPT

                     V      LVM;      means      8E      for      MBR      and
                            E6D6D379-F507-44C2-A23C-238F2A3DF928 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  parti-
              tions  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:

                            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.

                            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.

                            Mark the partition as bootable.

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

                            GPT partition UUID.

                            GPT partition name.

                            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

       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

       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

              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.

       Implicit coloring can be disabled by an empty  file  /etc/terminal-col-

       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.

              The welcome message.

       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-ex-
       tended,  --unhide,  --show-extended,  --cylinders,  --heads, --sectors,
       --inside-outer, --not-inside-outer options.

              enables sfdisk debug output.

              enables libfdisk debug output.

              enables libblkid debug output.

              enables libsmartcols debug output.

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

       Karel Zak <kzak@redhat.com>

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

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

util-linux                         June 2015                         SFDISK(8)
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