Provided by: fdisk_2.34-0.1ubuntu2_amd64 bug

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,  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.

       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 devices.

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  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 automatically 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 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 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  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-<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. This option is not supported
              when using the --show-size command.

       -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

       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.

                     first-lba
                            Specify the first usable sector for GPT partitions.

                     last-lba
                            Specify the last usable sector for GPT partitions.

                     table-length
                            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 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

                     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 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

       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

       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

       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
       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

       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
       https://www.kernel.org/pub/linux/utils/util-linux/.