1SFDISK(8) System Administration SFDISK(8)
2
6 sfdisk - display or manipulate a disk partition table
7
9 sfdisk [options] device [-N partition-number]
10 sfdisk [options] command
12
14 sfdisk is a script-oriented tool for partitioning any block device. It
15 runs in interactive mode if executed on a terminal (stdin refers to a
16 terminal).
17 Since version 2.26 sfdisk supports MBR (DOS), GPT, SUN and SGI disk
19 labels, but no longer provides any functionality for CHS
20 (Cylinder-Head-Sector) addressing. CHS has never been important for
21 Linux, and this addressing concept does not make any sense for new
22 devices.
23 sfdisk protects the first disk sector when create a new disk label. The
25 option --wipe always disables this protection. Note that fdisk(8) and
26 cfdisk(8) completely erase this area by default.
27 sfdisk (since version 2.26) aligns the start and end of partitions to
29 block-device I/O limits when relative sizes are specified, when the
30 default values are used or when multiplicative suffixes (e.g., MiB) are
31 used for sizes. It is possible that partition size will be optimized
32 (reduced or enlarged) due to alignment if the start offset is specified
33 exactly in sectors and partition size relative or by multiplicative
34 suffixes.
35 The recommended way is not to specify start offsets at all and specify
37 partition size in MiB, GiB (or so). In this case sfdisk aligns all
38 partitions to block-device I/O limits (or when I/O limits are too small
39 then to megabyte boundary to keep disk layout portable). If this
40 default behaviour is unwanted (usually for very small partitions) then
41 specify offsets and sizes in sectors. In this case sfdisk entirely
42 follows specified numbers without any optimization.
43 sfdisk does not create the standard system partitions for SGI and SUN
45 disk labels like fdisk(8) does. It is necessary to explicitly create
46 all partitions including whole-disk system partitions.
47 sfdisk uses BLKRRPART (reread partition table) ioctl to make sure that
49 the device is not used by system or other tools (see also --no-reread).
50 It’s possible that this feature or another sfdisk activity races with
51 systemd-udevd(8). The recommended way how to avoid possible collisions
52 is to use --lock option. The exclusive lock will cause systemd-udevd to
53 skip the event handling on the device.
54 The sfdisk prompt is only a hint for users and a displayed partition
56 number does not mean that the same partition table entry will be
57 created (if -N not specified), especially for tables with gaps.
58
60 The commands are mutually exclusive.
61 [-N partition-number] device
63 The default sfdisk command is to read the specification for the
64 desired partitioning of device from standard input, and then create
65 a partition table according to the specification. See below for the
66 description of the input format. If standard input is a terminal,
67 then sfdisk starts an interactive session.
68 If the option -N is specified, then the changes are applied to the
70 partition addressed by partition-number. The unspecified fields of
71 the partition are not modified.
72 Note that it’s possible to address an unused partition with -N. For
74 example, an MBR always contains 4 partitions, but the number of
75 used partitions may be smaller. In this case sfdisk follows the
76 default values from the partition table and does not use built-in
77 defaults for the unused partition given with -N. See also --append.
78 -A, --activate device [partition-number...]
80 Switch on the bootable flag for the specified partitions and switch
81 off the bootable flag on all unspecified partitions. The special
82 placeholder '-' may be used instead of the partition numbers to
83 switch off the bootable flag on all partitions.
84 The activation command is supported for MBR and PMBR only. If a GPT
86 label is detected, then sfdisk prints warning and automatically
87 enters PMBR.
88 If no partition-number is specified, then list the partitions with
90 an enabled flag.
91 --backup-pt-sectors device
93 Back up the current partition table sectors in binary format and
94 exit. See the BACKING UP THE PARTITION TABLE section.
95 --delete device [partition-number...]
97 Delete all or the specified partitions.
98 -d, --dump device
100 Dump the partitions of a device in a format that is usable as input
101 to sfdisk. See the BACKING UP THE PARTITION TABLE section.
102 -g, --show-geometry [device...]
104 List the geometry of all or the specified devices. For backward
105 compatibility the deprecated option --show-pt-geometry have the
106 same meaning as this one.
107 -J, --json device
109 Dump the partitions of a device in JSON format. Note that sfdisk is
110 not able to use JSON as input format.
111 -l, --list [device...]
113 List the partitions of all or the specified devices. This command
114 can be used together with --verify.
115 -F, --list-free [device...]
117 List the free unpartitioned areas on all or the specified devices.
118 --part-attrs device partition-number [attributes]
120 Change the GPT partition attribute bits. If attributes is not
121 specified, then print the current partition settings. The
122 attributes argument is a comma- or space-delimited list of bits
123 numbers or bit names. For example, the string
124 "RequiredPartition,50,51" sets three bits. The currently supported
125 attribute bits are:
126 Bit 0 (RequiredPartition)
128 If this bit is set, the partition is required for the platform
129 to function. The creator of the partition indicates that
130 deletion or modification of the contents can result in loss of
131 platform features or failure for the platform to boot or
132 operate. The system cannot function normally if this partition
133 is removed, and it should be considered part of the hardware of
134 the system.
135 Bit 1 (NoBlockIOProtocol)
137 EFI firmware should ignore the content of the partition and not
138 try to read from it.
139 Bit 2 (LegacyBIOSBootable)
141 The partition may be bootable by legacy BIOS firmware.
142 Bits 3-47
144 Undefined and must be zero. Reserved for expansion by future
145 versions of the UEFI specification.
146 Bits 48-63
148 Reserved for GUID specific use. The use of these bits will vary
149 depending on the partition type. For example Microsoft uses bit
150 60 to indicate read-only, 61 for shadow copy of another
151 partition, 62 for hidden partitions and 63 to disable
152 automount.
153 --part-label device partition-number [label]
155 Change the GPT partition name (label). If label is not specified,
156 then print the current partition label.
157 --part-type device partition-number [type]
159 Change the partition type. If type is not specified, then print the
160 current partition type.
161 The type argument is hexadecimal for MBR, GUID for GPT, type alias
163 (e.g. "linux") or type shortcut (e.g. 'L'). For backward
164 compatibility the options -c and --id have the same meaning as this
165 one.
166 --part-uuid device partition-number [uuid]
168 Change the GPT partition UUID. If uuid is not specified, then print
169 the current partition UUID.
170 --disk-id device [id]
172 Change the disk identifier. If id is not specified, then print the
173 current identifier. The identifier is UUID for GPT or unsigned
174 integer for MBR.
175 -r, --reorder device
177 Renumber the partitions, ordering them by their start offset.
178 -s, --show-size [device...]
180 List the sizes of all or the specified devices in units of 1024
181 byte size. This command is DEPRECATED in favour of blockdev(8).
182 -T, --list-types
184 Print all supported types for the current disk label or the label
185 specified by --label.
186 -V, --verify [device...]
188 Test whether the partition table and partitions seem correct.
189 --relocate oper device
191 Relocate partition table header. This command is currently
192 supported for GPT header only. The argument oper can be:
193 gpt-bak-std
195 Move GPT backup header to the standard location at the end of
196 the device.
197 gpt-bak-mini
199 Move GPT backup header behind the last partition. Note that
200 UEFI standard requires the backup header at the end of the
201 device and partitioning tools can automatically relocate the
202 header to follow the standard.
203
205 -a, --append
206 Don’t create a new partition table, but only append the specified
207 partitions.
208 Note that unused partition maybe be re-used in this case although
210 it is not the last partition in the partition table. See also -N to
211 specify entry in the partition table.
212 -b, --backup
214 Back up the current partition table sectors before starting the
215 partitioning. The default backup file name is
216 ~/sfdisk-<device>-<offset>.bak; to use another name see option -O,
217 --backup-file. See section BACKING UP THE PARTITION TABLE for more
218 details.
219 --color[=when]
221 Colorize the output. The optional argument when can be auto, never
222 or always. If the when argument is omitted, it defaults to auto.
223 The colors can be disabled; for the current built-in default see
224 the --help output. See also the COLORS section.
225 -f, --force
227 Disable all consistency checking.
228 --Linux
230 Deprecated and ignored option. Partitioning that is compatible with
231 Linux (and other modern operating systems) is the default.
232 --lock[=mode]
234 Use exclusive BSD lock for device or file it operates. The optional
235 argument mode can be yes, no (or 1 and 0) or nonblock. If the mode
236 argument is omitted, it defaults to yes. This option overwrites
237 environment variable $LOCK_BLOCK_DEVICE. The default is not to use
238 any lock at all, but it’s recommended to avoid collisions with
239 systemd-udevd(8) or other tools.
240 -n, --no-act
242 Do everything except writing to the device.
243 --no-reread
245 Do not check through the re-read-partition-table ioctl whether the
246 device is in use.
247 --no-tell-kernel
249 Don’t tell the kernel about partition changes. This option is
250 recommended together with --no-reread to modify a partition on used
251 disk. The modified partition should not be used (e.g., mounted).
252 -O, --backup-file path
254 Override the default backup file name. Note that the device name
255 and offset are always appended to the file name.
256 --move-data[=path]
258 Move data after partition relocation, for example when moving the
259 beginning of a partition to another place on the disk. The size of
260 the partition has to remain the same, the new and old location may
261 overlap. This option requires option -N in order to be processed on
262 one specific partition only.
263 The optional path specifies log file name. The log file contains
265 information about all read/write operations on the partition data.
266 The word "@default" as a path forces sfdisk to use
267 ~/sfdisk-<devname>.move for the log. The log is optional since
268 v2.35.
269 Note that this operation is risky and not atomic. Don’t forget to
271 backup your data!
272 See also --move-use-fsync.
274 In the example below, the first command creates a 100MiB free area
276 before the first partition and moves the data it contains (e.g., a
277 filesystem), the next command creates a new partition from the free
278 space (at offset 2048), and the last command reorders partitions to
279 match disk order (the original sdc1 will become sdc2).
280 echo '+100M,' | sfdisk --move-data /dev/sdc -N 1
282 echo '2048,' | sfdisk /dev/sdc --append
284 sfdisk /dev/sdc --reorder
286 --move-use-fsync
288 Use the fsync(2) system call after each write when moving data to a
289 new location by --move-data.
290 -o, --output list
292 Specify which output columns to print. Use --help to get a list of
293 all supported columns.
294 The default list of columns may be extended if list is specified in
296 the format +list (e.g., -o +UUID).
297 -q, --quiet
299 Suppress extra info messages.
300 -u, --unit S
302 Deprecated option. Only the sector unit is supported. This option
303 is not supported when using the --show-size command.
304 -X, --label type
306 Specify the disk label type (e.g., dos, gpt, ...). If this option
307 is not given, then sfdisk defaults to the existing label, but if
308 there is no label on the device yet, then the type defaults to dos.
309 The default or the current label may be overwritten by the "label:
310 <name>" script header line. The option --label does not force
311 sfdisk to create empty disk label (see the EMPTY DISK LABEL section
312 below).
313 -Y, --label-nested type
315 Force editing of a nested disk label. The primary disk label has to
316 exist already. This option allows editing for example a
317 hybrid/protective MBR on devices with GPT.
318 -w, --wipe when
320 Wipe filesystem, RAID and partition-table signatures from the
321 device, in order to avoid possible collisions. The argument when
322 can be auto, never or always. When this option is not given, the
323 default is auto, in which case signatures are wiped only when in
324 interactive mode; except the old partition-table signatures which
325 are always wiped before create a new partition-table if the
326 argument when is not never. The auto mode also does not wipe the
327 first sector (boot sector), it is necessary to use the always mode
328 to wipe this area. In all cases detected signatures are reported by
329 warning messages before a new partition table is created. See also
330 the wipefs(8) command.
331 -W, --wipe-partitions when
333 Wipe filesystem, RAID and partition-table signatures from a newly
334 created partition, in order to avoid possible collisions. The
335 argument when can be auto, never or always. When this option is not
336 given, the default is auto, in which case signatures are wiped only
337 when in interactive mode and after confirmation by user. In all
338 cases detected signatures are reported by warning messages after a
339 new partition is created. See also wipefs(8) command.
340 -v, --version
342 Display version information and exit.
343 -h, --help
345 Display help text and exit.
346
348 sfdisk supports two input formats and generic header lines.
349 Header lines
351 The optional header lines specify generic information that apply to the
352 partition table. The header-line format is:
353 <name>: <value>
355 The currently recognized headers are:
357 unit
359 Specify the partitioning unit. The only supported unit is sectors.
360 label
362 Specify the partition table type. For example dos or gpt.
363 label-id
365 Specify the partition table identifier. It should be a hexadecimal
366 number (with a 0x prefix) for MBR and a UUID for GPT.
367 first-lba
369 Specify the first usable sector for GPT partitions. This header is
370 ignored if the script and device sector size differ. In this case
371 sfdisk uses label specific default.
372 last-lba
374 Specify the last usable sector for GPT partitions. This header is
375 ignored if the script and device sector size differ. In this case
376 sfdisk uses label specific default.
377 table-length
379 Specify the maximal number of GPT partitions.
380 grain
382 Specify minimal size in bytes used to calculate partitions
383 alignment. The default is 1MiB and it’s strongly recommended to use
384 the default. Do not modify this variable if you’re not sure.
385 sector-size
387 Specify sector size. sfdisk always uses device sector size. Since
388 version 2.39 sfdisk recalculates sizes from dump if the script and
389 device sector size differ.
390 Note that it is only possible to use header lines before the first
392 partition is specified in the input.
393 Unnamed-fields format
395 start size type bootable
396 where each line fills one partition descriptor.
398 Fields are separated by whitespace, comma (recommended) or semicolon
400 possibly followed by whitespace; initial and trailing whitespace is
401 ignored. Numbers can be octal, decimal or hexadecimal; decimal is the
402 default. When a field is absent, empty or specified as '-' a default
403 value is used. But when the -N option (change a single partition) is
404 given, the default for each field is its previous value.
405 The default value of start is the first non-assigned sector aligned
407 according to device I/O limits. The default start offset for the first
408 partition is 1 MiB. If the offset is followed by the multiplicative
409 suffixes (KiB, MiB, GiB, TiB, PiB, EiB, ZiB and YiB), then the number
410 is interpreted as offset in bytes. Since v2.38 when the -N option
411 (change a single partition) is given, a '+' can be used to enlarge
412 partition by move start of the partition if there is a free space
413 before the partition.
414 The default value of size indicates "as much as possible"; i.e., until
416 the next partition or end-of-device. A numerical argument is by default
417 interpreted as a number of sectors, however if the size is followed by
418 one of the multiplicative suffixes (KiB, MiB, GiB, TiB, PiB, EiB, ZiB
419 and YiB) then the number is interpreted as the size of the partition in
420 bytes and it is then aligned according to the device I/O limits. A '+'
421 can be used instead of a number to enlarge the partition as much as
422 possible. Note '+' is equivalent to the default behaviour for a new
423 partition; existing partitions will be resized as required.
424 The partition type is given in hex for MBR (DOS) where 0x prefix is
426 optional; a GUID string for GPT; a shortcut or an alias. It’s
427 recommended to use two letters for MBR hex codes to avoid collision
428 between deprecated shortcut 'E' and '0E' MBR hex code. For backward
429 compatibility sfdisk tries to interpret type as a shortcut as a first
430 possibility in partitioning scripts although on other places (e.g.
431 --part-type command) it tries shortcuts as the last possibility.
432 Since v2.36 libfdisk supports partition type aliases as extension to
434 shortcuts. The alias is a simple human readable word (e.g. "linux").
435 Since v2.37 libfdisk supports partition type names on input, ignoring
437 the case of the characters and all non-alphanumeric and non-digit
438 characters in the name (e.g. "Linux /usr x86" is the same as "linux
439 usr-x86").
440 Supported shortcuts and aliases:
442 L - alias 'linux'
444 Linux; means 83 for MBR and 0FC63DAF-8483-4772-8E79-3D69D8477DE4
445 for GPT.
446 S - alias 'swap'
448 swap area; means 82 for MBR and
449 0657FD6D-A4AB-43C4-84E5-0933C84B4F4F for GPT
450 Ex - alias 'extended'
452 MBR extended partition; means 05 for MBR. The original shortcut 'E'
453 is deprecated due to collision with 0x0E MBR partition type.
454 H - alias 'home'
456 home partition; means 933AC7E1-2EB4-4F13-B844-0E14E2AEF915 for GPT
457 U - alias 'uefi'
459 EFI System partition, means EF for MBR and
460 C12A7328-F81F-11D2-BA4B-00A0C93EC93B for GPT
461 R - alias 'raid'
463 Linux RAID; means FD for MBR and
464 A19D880F-05FC-4D3B-A006-743F0F84911E for GPT
465 V - alias 'lvm'
467 LVM; means 8E for MBR and E6D6D379-F507-44C2-A23C-238F2A3DF928 for
468 GPT
469 The default type value is linux.
471 The shortcut 'X' for Linux extended partition (85) is deprecated in
473 favour of 'Ex'.
474 bootable is specified as [*|-], with as default not-bootable. The value
476 of this field is irrelevant for Linux - when Linux runs it has been
477 booted already - but it might play a role for certain boot loaders and
478 for other operating systems.
479 Named-fields format
481 This format is more readable, robust, extensible and allows specifying
482 additional information (e.g., a UUID). It is recommended to use this
483 format to keep your scripts more readable.
484 [device :] name[=value], ...
486 The device field is optional. sfdisk extracts the partition number from
488 the device name. It allows specifying the partitions in random order.
489 This functionality is mostly used by --dump. Don’t use it if you are
490 not sure.
491 The value can be between quotation marks (e.g., name="This is partition
493 name"). The fields start= and size= support '+' and '-' in the same way
494 as Unnamed-fields format.
495 The currently supported fields are:
497 start=number
499 The first non-assigned sector aligned according to device I/O
500 limits. The default start offset for the first partition is 1 MiB.
501 If the offset is followed by the multiplicative suffixes (KiB, MiB,
502 GiB, TiB, PiB, EiB, ZiB and YiB), then the number is interpreted as
503 offset in bytes.
504 size=number
506 Specify the partition size in sectors. The number may be followed
507 by the multiplicative suffixes (KiB, MiB, GiB, TiB, PiB, EiB, ZiB
508 and YiB), then it’s interpreted as size in bytes and the size is
509 aligned according to device I/O limits.
510 bootable
512 Mark the partition as bootable.
513 attrs=string
515 Partition attributes, usually GPT partition attribute bits. See
516 --part-attrs for more details about the GPT-bits string format.
517 uuid=string
519 GPT partition UUID.
520 name=string
522 GPT partition name.
523 type=code
525 A hexadecimal number (without 0x) for an MBR partition, a GUID for
526 a GPT partition, a shortcut as for unnamed-fields format or a type
527 name (e.g. type="Linux /usr (x86)"). See above the section about
528 the unnamed-fields format for more details. For backward
529 compatibility the Id= field has the same meaning.
530
532 sfdisk does not create partition table without partitions by default.
533 The lines with partitions are expected in the script by default. The
534 empty partition table has to be explicitly requested by "label: <name>"
535 script header line without any partitions lines. For example:
536 echo 'label: gpt' | sfdisk /dev/sdb
538 creates empty GPT partition table. Note that the --append disables this
540 feature.
541
543 It is recommended to save the layout of your devices. sfdisk supports
544 two ways.
545 Dump in sfdisk compatible format
547 Use the --dump command to save a description of the device layout to a
548 text file. The dump format is suitable for later sfdisk input. For
549 example:
550 sfdisk --dump /dev/sda > sda.dump
552 This can later be restored by:
554 sfdisk /dev/sda < sda.dump
556 Note that sfdisk completely restores partition types and partition
558 UUIDs. This could potentially become problematic if you duplicate the
559 same layout to different disks, as it may result in duplicate UUIDs
560 within your system.
561 Full binary backup
563 If you want to do a full binary backup of all sectors where the
564 partition table is stored, then use the --backup-pt-sectors command. It
565 writes the sectors to ~/sfdisk-<device>-<offset>.bak files. The default
566 name of the backup file can be changed with the --backup-file option.
567 The backup files contain only raw data from the device. For example:
568 sfdisk --backup-pt-sectors /dev/sda
570 The GPT header can later be restored by:
572 dd if=~/sfdisk-sda-0x00000200.bak of=/dev/sda
574 seek=$((0x00000200)) bs=1 conv=notrunc
575 It’s also possible to use the --backup option to create the same backup
577 immediately after startup for other sfdisk commands. For example,
578 backup partition table before deleting all partitions from partition
579 table:
580 sfdisk --backup --delete /dev/sda
582 The same concept of backup files is used by wipefs(8).
584 Note that sfdisk since version 2.26 no longer provides the -I option to
586 restore sectors. dd(1) provides all necessary functionality.
587
589 The output colorization is implemented by terminal-colors.d(5)
590 functionality. Implicit coloring can be disabled by an empty file
591 /etc/terminal-colors.d/sfdisk.disable
593 for the sfdisk command or for all tools by
595 /etc/terminal-colors.d/disable
597 The user-specific $XDG_CONFIG_HOME/terminal-colors.d or
599 $HOME/.config/terminal-colors.d overrides the global setting.
600 Note that the output colorization may be enabled by default, and in
602 this case terminal-colors.d directories do not have to exist yet.
603 The logical color names supported by sfdisk are:
605 header
607 The header of the output tables.
608 warn
610 The warning messages.
611 welcome
613 The welcome message.
614
616 SFDISK_DEBUG=all
617 enables sfdisk debug output.
618 LIBFDISK_DEBUG=all
620 enables libfdisk debug output.
621 LIBBLKID_DEBUG=all
623 enables libblkid debug output.
624 LIBSMARTCOLS_DEBUG=all
626 enables libsmartcols debug output.
627 LOCK_BLOCK_DEVICE=<mode>
629 use exclusive BSD lock. The mode is "1" or "0". See --lock for more
630 details.
631
633 Since version 2.26 sfdisk no longer provides the -R or --re-read option
634 to force the kernel to reread the partition table. Use blockdev
635 --rereadpt instead.
636 Since version 2.26 sfdisk does not provide the --DOS, --IBM,
638 --DOS-extended, --unhide, --show-extended, --cylinders, --heads,
639 --sectors, --inside-outer, --not-inside-outer options.
640
642 sfdisk --list --label-nested=mbr /dev/sda
643 Print protective MBR on device with GPT disk label.
644 echo -e ',10M,L\n,10M,L\n,+,\n' | sfdisk /dev/sdc
646 Create three Linux partitions, with the default start, the size of
647 the first two partitions is 10MiB, and the last partition fills all
648 available space on the device.
649 echo -e 'size=10M, type=L\n size=10M, type=L\n size=+\n' | sfdisk
651 /dev/sdc
652 The same as the previous example, but in named-fields format.
653 echo -e 'type=swap' | sfdisk -N 3 /dev/sdc
655 Set type of the 3rd partition to 'swap'.
656 sfdisk --part-type /dev/sdc 3 swap
658 The same as the previous example, but without script use.
659 sfdisk --delete /dev/sdc 2
661 Delete 2nd partition.
662 echo "+,+" | sfdisk -N 3 --move-data /dev/sdc
664 Enlarge 3rd partition in both directions, move start to use free
665 space before the partition and enlarge the size to use all free
666 space after to the partition, and move partition data too.
667
669 Karel Zak <kzak@redhat.com>
670 The current sfdisk implementation is based on the original sfdisk from
672 Andries E. Brouwer.
673
675 fdisk(8), cfdisk(8), parted(8), partprobe(8), partx(8)
676
678 For bug reports, use the issue tracker at
679 https://github.com/util-linux/util-linux/issues.
680
682 The sfdisk command is part of the util-linux package which can be
683 downloaded from Linux Kernel Archive
684 <https://www.kernel.org/pub/linux/utils/util-linux/>.
685util-linux 2.39.2 2023-06-21 SFDISK(8)