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NAME | SYNOPSIS | DESCRIPTION | COMMANDS | OPTIONS | INPUT FORMATS | EMPTY DISK LABEL | BACKING UP THE PARTITION TABLE | COLORS | ENVIRONMENT | NOTES | AUTHORS | SEE ALSO | AVAILABILITY | COLOPHON |
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.
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 (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). It's possible that this feature or another sfdisk activity
races with udevd. The recommended way how to avoid possible
collisions is to use --lock option. The exclusive lock will cause
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.
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
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.
--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, 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.
-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.
-a, --append
Don't 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-<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.
--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 it's recommended to avoid collisions with udevd 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
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 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-<devname>.move for the log. The log is optional
since v2.35.
Note that this operation is risky and not atomic. Don't 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.
-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 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. 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 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.
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.
sector-size
Specify sector size. This header is informative only and it is
not used when sfdisk creates a new partition table, in this
case the real device specific value is always used and sector
size from the dump is ignored.
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) where 0x prefix is
optional; a GUID string for GPT; a shortcut or an alias. It's
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").
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. 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, a GUID
for a GPT partition, or a shortcut as for unnamed-fields
format. For backward compatibility the Id= field has the same
meaning.
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.
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.
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.
SFDISK_DEBUG=all
enablescw 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=<mode>
use exclusive BSD lock. The mode is "1" or "0". See --lock
for more details.
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.
Karel Zak <kzak@redhat.com>
The current sfdisk implementation is based on the original sfdisk
from Andries E. Brouwer.
fdisk(8), cfdisk(8), parted(8), partprobe(8), partx(8)
The sfdisk command is part of the util-linux package and is available
from https://www.kernel.org/pub/linux/utils/util-linux/.
This page is part of the util-linux (a random collection of Linux
utilities) project. Information about the project can be found at
⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩. If you have a
bug report for this manual page, send it to
util-linux@vger.kernel.org. This page was obtained from the
project's upstream Git repository
⟨git://git.kernel.org/pub/scm/utils/util-linux/util-linux.git⟩ on
2020-08-13. (At that time, the date of the most recent commit that
was found in the repository was 2020-08-12.) If you discover any
rendering problems in this HTML version of the page, or you believe
there is a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
util-linux June 2015 SFDISK(8)
Pages that refer to this page: repart.d(5) , cfdisk(8) , fdisk(8)