Manual: sfdisk
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. It runs in interactive mode if executed on a
terminal (stdin refers to a terminal).
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 protects the first disk sector when create a new disk label. The option --wipe always disables this
protection. Note that fdisk(8) and cfdisk(8) completely erase this area by default.
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 aligns 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 other
tools (see also --no-reread). Itâs possible that this feature or another sfdisk activity races with systemd-udevd(8).
The recommended way how to avoid possible collisions is to use --lock option. The exclusive lock will cause
systemd-udevd to skip the event handling on the device.
The sfdisk prompt is only a hint for users and a displayed partition number does not mean that the same partition
table entry will be created (if -N not specified), especially for tables with gaps.
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 itâs 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 a GPT label is detected, then sfdisk prints warning
and automatically enters PMBR.
If no partition-number is specified, then list the partitions with an enabled flag.
--backup-pt-sectors device
Back up the current partition table sectors in binary format and exit. See the BACKING UP THE PARTITION TABLE
section.
--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 BACKING UP THE PARTITION
TABLE section.
-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 numbers or bit names. For example,
the string "RequiredPartition,50,51" sets three bits. The currently supported attribute bits are:
Bit 0 (RequiredPartition)
If this bit is set, the partition is required for the platform to function. The creator of the partition
indicates that deletion or modification of the contents can result in loss of platform features or failure
for the platform to boot or operate. The system cannot function normally if this partition is removed, and it
should be considered part of the hardware of the system.
Bit 1 (NoBlockIOProtocol)
EFI firmware should ignore the content of the partition and not try to read from it.
Bit 2 (LegacyBIOSBootable)
The partition may be bootable by legacy BIOS firmware.
Bits 3-47
Undefined and must be zero. Reserved for expansion by future versions of the UEFI specification.
Bits 48-63
Reserved for GUID specific use. The use of these bits will vary depending on the partition type. For example
Microsoft uses bit 60 to indicate read-only, 61 for shadow copy of another partition, 62 for hidden
partitions and 63 to disable automount.
--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, GUID for GPT, type alias (e.g. "linux") or type shortcut (e.g. 'L').
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.
--disk-id device [id]
Change the disk identifier. If id is not specified, then print the current identifier. The identifier is UUID for
GPT or unsigned integer for MBR.
--discard-free device
Discard any unused (unpartitioned) sectors on the device. Use the --list-free option to get a list of the free
regions. See also blkdiscard(8).
Warning
All data in the discarded regions on the device will be lost! Do not use this option if you are unsure.
Note that the 'T' command in fdisk provides a dialog to specify which unused area should be discarded. However,
sfdisk always discards all unpartitioned regions (except for the areas where it is not possible to create
partitions, such as the beginning of the device).
-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(8).
-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.
--relocate oper device
Relocate partition table header. This command is currently supported for GPT header only. The argument oper can
be:
gpt-bak-std
Move GPT backup header to the standard location at the end of the device.
gpt-bak-mini
Move GPT backup header behind the last partition. Note that UEFI standard requires the backup header at the
end of the device and partitioning tools can automatically relocate the header to follow the standard.
OPTIONS
-a, --append
Donât create a new partition table, but only append the specified partitions.
Note that unused partition maybe be re-used in this case although it is not the last partition in the partition
table. See also -N to specify entry in the partition table.
-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. See section BACKING UP THE
PARTITION TABLE for more details.
--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.
--lock[=mode]
Use exclusive BSD lock for device or file it operates. The optional argument mode can be yes, no (or 1 and 0) or
nonblock. If the mode argument is omitted, it defaults to yes. This option overwrites environment variable
$LOCK_BLOCK_DEVICE. The default is not to use any lock at all, but itâs recommended to avoid collisions with
systemd-udevd(8) or other tools.
-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
Donât 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 optional path specifies log file name. The log file contains information about all read/write operations on
the partition data. The word "@default" as a path forces sfdisk to use ~/sfdisk-.move for the log. The
log is optional since v2.35.
Note that this operation is risky and not atomic. Donât forget to backup your data!
See also --move-use-fsync.
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
--move-use-fsync
Use the fsync(2) system call after each write when moving data to a new location by --move-data.
-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.
--sector-size sectorsize
Specify the sector size of the disk. Valid values are 512, 1024, 2048, and 4096. The kernel is aware of the
sector size for regular block devices. Use this option only on very old kernels, when working with disk images,
or to override the kernelâs default sector size. Since util-linux-2.17, fdisk distinguishes between logical and
physical sector size. This option changes both sector sizes to the specified sectorsize.
-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: " 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 editing 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. The auto mode also does not wipe the
first sector (boot sector), it is necessary to use the always mode to wipe this area. In all cases detected
signatures are reported by warning messages before a new partition table is created. See also the wipefs(8)
command.
-W, --wipe-partitions when
Wipe filesystem, RAID and partition-table signatures from a newly created partition, 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:
:
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. This header is ignored if the script and device sector size
differ. In this case sfdisk uses label specific default.
last-lba
Specify the last usable sector for GPT partitions. This header is ignored if the script and device sector size
differ. In this case sfdisk uses label specific default. The last-lba header is ignored if --force is specified,
making the script usable on disks with different sizes.
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 itâs strongly
recommended to use the default. Do not modify this variable if youâre not sure.
sector-size
Specifies the sector size used in the input. sfdisk always internally uses the device sector size provided by the
kernel for the block device, or as specified by the user on the command line (see --sector-size). Starting with
version 2.39, sfdisk recalculates sizes from the input if the sector-size header and device sector size are
different.
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 (recommended) 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. If the offset is followed by the multiplicative suffixes (KiB, MiB, GiB,
TiB, PiB, EiB, ZiB and YiB), then the number is interpreted as offset in bytes. Since v2.38 when the -N option
(change a single partition) is given, a '+' can be used to enlarge partition by move start of the partition if there
is a free space before the partition.
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) where 0x prefix is optional; a GUID string for GPT; a shortcut or an
alias. Itâs recommended to use two letters for MBR hex codes to avoid collision between deprecated shortcut 'E' and
'0E' MBR hex code. For backward compatibility sfdisk tries to interpret type as a shortcut as a first possibility in
partitioning scripts although on other places (e.g. --part-type command) it tries shortcuts as the last possibility.
Since v2.36 libfdisk supports partition type aliases as extension to shortcuts. The alias is a simple human readable
word (e.g. "linux").
Since v2.37 libfdisk supports partition type names on input, ignoring the case of the characters and all
non-alphanumeric and non-digit characters in the name (e.g. "Linux /usr x86" is the same as "linux usr-x86").
Supported shortcuts and aliases:
L - alias 'linux'
Linux; means 83 for MBR and 0FC63DAF-8483-4772-8E79-3D69D8477DE4 for GPT.
S - alias 'swap'
swap area; means 82 for MBR and 0657FD6D-A4AB-43C4-84E5-0933C84B4F4F for GPT
Ex - alias 'extended'
MBR extended partition; means 05 for MBR. The original shortcut 'E' is deprecated due to collision with 0x0E MBR
partition type.
H - alias 'home'
home partition; means 933AC7E1-2EB4-4F13-B844-0E14E2AEF915 for GPT
U - alias 'uefi'
EFI System partition, means EF for MBR and C12A7328-F81F-11D2-BA4B-00A0C93EC93B for GPT
R - alias 'raid'
Linux RAID; means FD for MBR and A19D880F-05FC-4D3B-A006-743F0F84911E for GPT
V - alias 'lvm'
LVM; means 8E for MBR and E6D6D379-F507-44C2-A23C-238F2A3DF928 for GPT
The default type value is linux.
The shortcut 'X' for Linux extended partition (85) is deprecated in favour of 'Ex'.
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 it 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 specifying 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 specifying the
partitions in random order. This functionality is mostly used by --dump. Donât use it if you are not sure.
The value can be between quotation marks (e.g., name="This is partition name"). The fields start= and size= support
'+' and '-' in the same way as Unnamed-fields format.
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. If the offset is 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 itâs 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, a GUID for a GPT partition, a shortcut as for
unnamed-fields format or a type name (e.g. type="Linux /usr (x86)"). See above the section about the
unnamed-fields format for more details. 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: " 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.
Dump in sfdisk compatible format
Use the --dump command 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
Note that sfdisk completely restores partition types and partition UUIDs. This could potentially become problematic
if you duplicate the same layout to different disks, as it may result in duplicate UUIDs within your system.
Full binary backup
If you want to do a full binary backup of all sectors where the partition table is stored, then use the
--backup-pt-sectors command. 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. For
example:
sfdisk --backup-pt-sectors /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
Itâs also possible to use the --backup option to create the same backup immediately after startup for other sfdisk
commands. For example, backup partition table before deleting all partitions from partition table:
sfdisk --backup --delete /dev/sda
The same concept of backup files is used by wipefs(8).
Note that sfdisk since version 2.26 no longer provides the -I option to restore sectors. dd(1) provides all necessary
functionality.
COLORS
The output colorization is implemented by terminal-colors.d(5) functionality. Implicit coloring can be disabled by an
empty file
/etc/terminal-colors.d/sfdisk.disable
for the sfdisk command or for all tools by
/etc/terminal-colors.d/disable
Since version 2.41, the $NO_COLOR environment variable is also supported to disable output colorization unless
explicitly enabled by a command-line option.
The user-specific $XDG_CONFIG_HOME/terminal-colors.d or $HOME/.config/terminal-colors.d overrides the global setting.
Note that the output colorization may be enabled by default, and in this case terminal-colors.d directories do not
have to exist yet.
The logical color names supported by sfdisk are:
header
The header of the output tables.
warn
The warning messages.
welcome
The welcome message.
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.
LOCK_BLOCK_DEVICE=
use exclusive BSD lock. The mode is "1" or "0". See --lock for more details.
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.
EXAMPLES
sfdisk --list --label-nested=mbr /dev/sda
Print protective MBR on device with GPT disk label.
echo -e ',10M,L\n,10M,L\n,+,\n' | sfdisk /dev/sdc
Create three Linux partitions, with the default start, the size of the first two partitions is 10MiB, and the
last partition fills all available space on the device.
echo -e 'size=10M, type=L\n size=10M, type=L\n size=+\n' | sfdisk /dev/sdc
The same as the previous example, but in named-fields format.
echo -e 'type=swap' | sfdisk -N 3 /dev/sdc
Set type of the 3rd partition to 'swap'.
sfdisk --part-type /dev/sdc 3 swap
The same as the previous example, but without script use.
sfdisk --delete /dev/sdc 2
Delete 2nd partition.
echo "+,+" | sfdisk -N 3 --move-data /dev/sdc
Enlarge 3rd partition in both directions, move start to use free space before the partition and enlarge the size
to use all free space after to the partition, and move partition data too.
AUTHORS
Karel Zak
The current sfdisk implementation is based on the original sfdisk from Andries E. Brouwer.
SEE ALSO
fdisk(8), cfdisk(8), parted(8), partprobe(8), partx(8)
REPORTING BUGS
For bug reports, use the issue tracker .
AVAILABILITY
The sfdisk command is part of the util-linux package which can be downloaded from Linux Kernel Archive
.
util-linux 2.41.3 2025-12-15 SFDISK(8)