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 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

   -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.

   -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.  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.

          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.

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





Opportunity


Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.

Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.





Free Software


Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.


Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.





Free Books


The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.


Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.





Education


Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.


Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.