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 echo '2048,' |
282 sfdisk /dev/sdc --append sfdisk /dev/sdc --reorder
283 --move-use-fsync
285 Use the fsync(2) system call after each write when moving data to a
286 new location by --move-data.
287 -o, --output list
289 Specify which output columns to print. Use --help to get a list of
290 all supported columns.
291 The default list of columns may be extended if list is specified in
293 the format +list (e.g., -o +UUID).
294 -q, --quiet
296 Suppress extra info messages.
297 -u, --unit S
299 Deprecated option. Only the sector unit is supported. This option
300 is not supported when using the --show-size command.
301 -X, --label type
303 Specify the disk label type (e.g., dos, gpt, ...). If this option
304 is not given, then sfdisk defaults to the existing label, but if
305 there is no label on the device yet, then the type defaults to dos.
306 The default or the current label may be overwritten by the "label:
307 <name>" script header line. The option --label does not force
308 sfdisk to create empty disk label (see the EMPTY DISK LABEL section
309 below).
310 -Y, --label-nested type
312 Force editing of a nested disk label. The primary disk label has to
313 exist already. This option allows editing for example a
314 hybrid/protective MBR on devices with GPT.
315 -w, --wipe when
317 Wipe filesystem, RAID and partition-table signatures from the
318 device, in order to avoid possible collisions. The argument when
319 can be auto, never or always. When this option is not given, the
320 default is auto, in which case signatures are wiped only when in
321 interactive mode; except the old partition-table signatures which
322 are always wiped before create a new partition-table if the
323 argument when is not never. The auto mode also does not wipe the
324 first sector (boot sector), it is necessary to use the always mode
325 to wipe this area. In all cases detected signatures are reported by
326 warning messages before a new partition table is created. See also
327 the wipefs(8) command.
328 -W, --wipe-partitions when
330 Wipe filesystem, RAID and partition-table signatures from a newly
331 created partition, in order to avoid possible collisions. The
332 argument when can be auto, never or always. When this option is not
333 given, the default is auto, in which case signatures are wiped only
334 when in interactive mode and after confirmation by user. In all
335 cases detected signatures are reported by warning messages after a
336 new partition is created. See also wipefs(8) command.
337 -v, --version
339 Display version information and exit.
340 -h, --help
342 Display help text and exit.
343
345 sfdisk supports two input formats and generic header lines.
346 Header lines
348 The optional header lines specify generic information that apply to the
349 partition table. The header-line format is:
350 <name>: <value>
352 The currently recognized headers are:
354 unit
356 Specify the partitioning unit. The only supported unit is sectors.
357 label
359 Specify the partition table type. For example dos or gpt.
360 label-id
362 Specify the partition table identifier. It should be a hexadecimal
363 number (with a 0x prefix) for MBR and a UUID for GPT.
364 first-lba
366 Specify the first usable sector for GPT partitions.
367 last-lba
369 Specify the last usable sector for GPT partitions.
370 table-length
372 Specify the maximal number of GPT partitions.
373 grain
375 Specify minimal size in bytes used to calculate partitions
376 alignment. The default is 1MiB and it’s strongly recommended to use
377 the default. Do not modify this variable if you’re not sure.
378 sector-size
380 Specify sector size. This header is informative only and it is not
381 used when sfdisk creates a new partition table, in this case the
382 real device specific value is always used and sector size from the
383 dump is ignored.
384 Note that it is only possible to use header lines before the first
386 partition is specified in the input.
387 Unnamed-fields format
389 start size type bootable
390 where each line fills one partition descriptor.
392 Fields are separated by whitespace, comma (recommended) or semicolon
394 possibly followed by whitespace; initial and trailing whitespace is
395 ignored. Numbers can be octal, decimal or hexadecimal; decimal is the
396 default. When a field is absent, empty or specified as '-' a default
397 value is used. But when the -N option (change a single partition) is
398 given, the default for each field is its previous value.
399 The default value of start is the first non-assigned sector aligned
401 according to device I/O limits. The default start offset for the first
402 partition is 1 MiB. If the offset is followed by the multiplicative
403 suffixes (KiB, MiB, GiB, TiB, PiB, EiB, ZiB and YiB), then the number
404 is interpreted as offset in bytes. Since v2.38 when the -N option
405 (change a single partition) is given, a '+' can be used to enlarge
406 partition by move start of the partition if there is a free space
407 before the partition.
408 The default value of size indicates "as much as possible"; i.e., until
410 the next partition or end-of-device. A numerical argument is by default
411 interpreted as a number of sectors, however if the size is followed by
412 one of the multiplicative suffixes (KiB, MiB, GiB, TiB, PiB, EiB, ZiB
413 and YiB) then the number is interpreted as the size of the partition in
414 bytes and it is then aligned according to the device I/O limits. A '+'
415 can be used instead of a number to enlarge the partition as much as
416 possible. Note '+' is equivalent to the default behaviour for a new
417 partition; existing partitions will be resized as required.
418 The partition type is given in hex for MBR (DOS) where 0x prefix is
420 optional; a GUID string for GPT; a shortcut or an alias. It’s
421 recommended to use two letters for MBR hex codes to avoid collision
422 between deprecated shortcut 'E' and '0E' MBR hex code. For backward
423 compatibility sfdisk tries to interpret type as a shortcut as a first
424 possibility in partitioning scripts although on other places (e.g.
425 --part-type command) it tries shortcuts as the last possibility.
426 Since v2.36 libfdisk supports partition type aliases as extension to
428 shortcuts. The alias is a simple human readable word (e.g. "linux").
429 Since v2.37 libfdisk supports partition type names on input, ignoring
431 the case of the characters and all non-alphanumeric and non-digit
432 characters in the name (e.g. "Linux /usr x86" is the same as "linux
433 usr-x86").
434 Supported shortcuts and aliases:
436 L - alias 'linux'
438 Linux; means 83 for MBR and 0FC63DAF-8483-4772-8E79-3D69D8477DE4
439 for GPT.
440 S - alias 'swap'
442 swap area; means 82 for MBR and
443 0657FD6D-A4AB-43C4-84E5-0933C84B4F4F for GPT
444 Ex - alias 'extended'
446 MBR extended partition; means 05 for MBR. The original shortcut 'E'
447 is deprecated due to collision with 0x0E MBR partition type.
448 H - alias 'home'
450 home partition; means 933AC7E1-2EB4-4F13-B844-0E14E2AEF915 for GPT
451 U - alias 'uefi'
453 EFI System partition, means EF for MBR and
454 C12A7328-F81F-11D2-BA4B-00A0C93EC93B for GPT
455 R - alias 'raid'
457 Linux RAID; means FD for MBR and
458 A19D880F-05FC-4D3B-A006-743F0F84911E for GPT
459 V - alias 'lvm'
461 LVM; means 8E for MBR and E6D6D379-F507-44C2-A23C-238F2A3DF928 for
462 GPT
463 The default type value is linux.
465 The shortcut 'X' for Linux extended partition (85) is deprecated in
467 favour of 'Ex'.
468 bootable is specified as [*|-], with as default not-bootable. The value
470 of this field is irrelevant for Linux - when Linux runs it has been
471 booted already - but it might play a role for certain boot loaders and
472 for other operating systems.
473 Named-fields format
475 This format is more readable, robust, extensible and allows specifying
476 additional information (e.g., a UUID). It is recommended to use this
477 format to keep your scripts more readable.
478 [device :] name[=value], ...
480 The device field is optional. sfdisk extracts the partition number from
482 the device name. It allows specifying the partitions in random order.
483 This functionality is mostly used by --dump. Don’t use it if you are
484 not sure.
485 The value can be between quotation marks (e.g., name="This is partition
487 name"). The fields start= and size= support '+' and '-' in the same way
488 as Unnamed-fields format.
489 The currently supported fields are:
491 start=number
493 The first non-assigned sector aligned according to device I/O
494 limits. The default start offset for the first partition is 1 MiB.
495 If the offset is followed by the multiplicative suffixes (KiB, MiB,
496 GiB, TiB, PiB, EiB, ZiB and YiB), then the number is interpreted as
497 offset in bytes.
498 size=number
500 Specify the partition size in sectors. The number may be followed
501 by the multiplicative suffixes (KiB, MiB, GiB, TiB, PiB, EiB, ZiB
502 and YiB), then it’s interpreted as size in bytes and the size is
503 aligned according to device I/O limits.
504 bootable
506 Mark the partition as bootable.
507 attrs=string
509 Partition attributes, usually GPT partition attribute bits. See
510 --part-attrs for more details about the GPT-bits string format.
511 uuid=string
513 GPT partition UUID.
514 name=string
516 GPT partition name.
517 type=code
519 A hexadecimal number (without 0x) for an MBR partition, a GUID for
520 a GPT partition, a shortcut as for unnamed-fields format or a type
521 name (e.g. type="Linux /usr (x86)"). See above the section about
522 the unnamed-fields format for more details. For backward
523 compatibility the Id= field has the same meaning.
524
526 sfdisk does not create partition table without partitions by default.
527 The lines with partitions are expected in the script by default. The
528 empty partition table has to be explicitly requested by "label: <name>"
529 script header line without any partitions lines. For example:
530 echo 'label: gpt' | sfdisk /dev/sdb
532 creates empty GPT partition table. Note that the --append disables this
534 feature.
535
537 It is recommended to save the layout of your devices. sfdisk supports
538 two ways.
539 Dump in sfdisk compatible format
541 Use the --dump command to save a description of the device layout to a
542 text file. The dump format is suitable for later sfdisk input. For
543 example:
544 sfdisk --dump /dev/sda > sda.dump
546 This can later be restored by:
548 sfdisk /dev/sda < sda.dump
550 Full binary backup
552 If you want to do a full binary backup of all sectors where the
553 partition table is stored, then use the --backup-pt-sectors command. It
554 writes the sectors to ~/sfdisk-<device>-<offset>.bak files. The default
555 name of the backup file can be changed with the --backup-file option.
556 The backup files contain only raw data from the device. For example:
557 sfdisk --backup-pt-sectors /dev/sda
559 The GPT header can later be restored by:
561 dd if=~/sfdisk-sda-0x00000200.bak of=/dev/sda
563 seek=$((0x00000200)) bs=1 conv=notrunc
564 It’s also possible to use the --backup option to create the same backup
566 immediately after startup for other sfdisk commands. For example,
567 backup partition table before deleting all partitions from partition
568 table:
569 sfdisk --backup --delete /dev/sda
571 The same concept of backup files is used by wipefs(8).
573 Note that sfdisk since version 2.26 no longer provides the -I option to
575 restore sectors. dd(1) provides all necessary functionality.
576
578 The output colorization is implemented by terminal-colors.d(5)
579 functionality. Implicit coloring can be disabled by an empty file
580 /etc/terminal-colors.d/sfdisk.disable
582 for the sfdisk command or for all tools by
584 /etc/terminal-colors.d/disable
586 The user-specific $XDG_CONFIG_HOME/terminal-colors.d or
588 $HOME/.config/terminal-colors.d overrides the global setting.
589 Note that the output colorization may be enabled by default, and in
591 this case terminal-colors.d directories do not have to exist yet.
592 The logical color names supported by sfdisk are:
594 header
596 The header of the output tables.
597 warn
599 The warning messages.
600 welcome
602 The welcome message.
603
605 SFDISK_DEBUG=all
606 enables sfdisk debug output.
607 LIBFDISK_DEBUG=all
609 enables libfdisk debug output.
610 LIBBLKID_DEBUG=all
612 enables libblkid debug output.
613 LIBSMARTCOLS_DEBUG=all
615 enables libsmartcols debug output.
616 LOCK_BLOCK_DEVICE=<mode>
618 use exclusive BSD lock. The mode is "1" or "0". See --lock for more
619 details.
620
622 Since version 2.26 sfdisk no longer provides the -R or --re-read option
623 to force the kernel to reread the partition table. Use blockdev
624 --rereadpt instead.
625 Since version 2.26 sfdisk does not provide the --DOS, --IBM,
627 --DOS-extended, --unhide, --show-extended, --cylinders, --heads,
628 --sectors, --inside-outer, --not-inside-outer options.
629
631 sfdisk --list --label-nested=mbr /dev/sda
632 Print protective MBR on device with GPT disk label.
633 echo -e ',10M,L\n,10M,L\n,+,\n' | sfdisk /dev/sdc
635 Create three Linux partitions, with the default start, the size of
636 the first two partitions is 10MiB, and the last partition fills all
637 available space on the device.
638 echo -e 'size=10M, type=L\n size=10M, type=L\n size=+\n' | sfdisk
640 /dev/sdc
641 The same as the previous example, but in named-fields format.
642 echo -e 'type=swap' | sfdisk -N 3 /dev/sdc
644 Set type of the 3rd partition to 'swap'.
645 sfdisk --part-type /dev/sdc 3 swap
647 The same as the previous example, but without script use.
648 sfdisk --delete /dev/sdc 2
650 Delete 2nd partition.
651 echo "," | sfdisk -N 3 --move-data /dev/sdc
653 Enlarge 3rd partition in both directions, move start to use free
654 space before the partition and enlarge the size to use all free
655 space after to the partition, and move partition data too.
656
658 Karel Zak <kzak@redhat.com>
659 The current sfdisk implementation is based on the original sfdisk from
661 Andries E. Brouwer.
662
664 fdisk(8), cfdisk(8), parted(8), partprobe(8), partx(8)
665
667 For bug reports, use the issue tracker at
668 https://github.com/util-linux/util-linux/issues.
669
671 The sfdisk command is part of the util-linux package which can be
672 downloaded from Linux Kernel Archive
673 <https://www.kernel.org/pub/linux/utils/util-linux/>.
674util-linux 2.38.1 2022-08-04 SFDISK(8)