{ "mode": "man", "parameter": "sgdisk", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/sgdisk/8/json", "generated": "2026-10-08T19:47:13Z", "synopsis": "sgdisk [ options ] device", "sections": { "NAME": { "content": "sgdisk - Command-line GUID partition table (GPT) manipulator for Linux and Unix\n", "subsections": [] }, "SYNOPSIS": { "content": "sgdisk [ options ] device\n\n", "subsections": [] }, "DESCRIPTION": { "content": "GPT fdisk is a text-mode menu-driven package for creation and manipulation of partition ta‐\nbles. It consists of two programs: the text-mode interactive gdisk and the command-line\nsgdisk. Either program will automatically convert an old-style Master Boot Record (MBR) par‐\ntition table or BSD disklabel stored without an MBR carrier partition to the newer Globally\nUnique Identifier (GUID) Partition Table (GPT) format, or will load a GUID partition table.\nThis man page documents the command-line sgdisk program.\n\nSome advanced data manipulation and recovery options require you to understand the distinc‐\ntions between the main and backup data, as well as between the GPT headers and the partition\ntables. For information on MBR vs. GPT, as well as GPT terminology and structure, see the ex‐\ntended gdisk documentation at https://www.rodsbooks.com/gdisk/ or consult Wikipedia.\n\nThe sgdisk program employs a user interface that's based entirely on the command line, making\nit suitable for use in scripts or by experts who want to make one or two quick changes to a\ndisk. (The program may query the user when certain errors are encountered, though.) The pro‐\ngram's name is based on sfdisk, but the user options of the two programs are entirely differ‐\nent from one another.\n\nOrdinarily, sgdisk operates on disk device files, such as /dev/sda or /dev/hda under Linux,\n/dev/disk0 under Mac OS X, or /dev/ad0 or /dev/da0 under FreeBSD. The program can also oper‐\nate on disk image files, which can be either copies of whole disks (made with dd, for in‐\nstance) or raw disk images used by emulators such as QEMU or VMWare. Note that only raw disk\nimages are supported; sgdisk cannot work on compressed or other advanced disk image formats.\n\nThe MBR partitioning system uses a combination of cylinder/head/sector (CHS) addressing and\nlogical block addressing (LBA). The former is klunky and limiting. GPT drops CHS addressing\nand uses 64-bit LBA mode exclusively. Thus, GPT data structures, and therefore sgdisk, do not\nneed to deal with CHS geometries and all the problems they create.\n\nFor best results, you should use an OS-specific partition table program whenever possible.\nFor example, you should make Mac OS X partitions with the Mac OS X Disk Utility program and\nLinux partitions with the Linux gdisk, sgdisk, or GNU Parted programs.\n\nUpon start, sgdisk attempts to identify the partition type in use on the disk. If it finds\nvalid GPT data, sgdisk will use it. If sgdisk finds a valid MBR or BSD disklabel but no GPT\ndata, it will attempt to convert the MBR or disklabel into GPT form. (BSD disklabels are\nlikely to have unusable first and/or final partitions because they overlap with the GPT data\nstructures, though.) GPT fdisk can identify, but not use data in, Apple Partition Map (APM)\ndisks, which are used on 680x0- and PowerPC-based Macintoshes. If you specify any option that\nresults in changes to an MBR or BSD disklabel, sgdisk ignores those changes unless the -g\n(--mbrtogpt), -z (--zap), or -Z (--zap-all) option is used. If you use the -g option, sgdisk\nreplaces the MBR or disklabel with a GPT. This action is potentially dangerous! Your system\nmay become unbootable, and partition type codes may become corrupted if the disk uses unrec‐\nognized type codes. Boot problems are particularly likely if you're multi-booting with any\nGPT-unaware OS.\n\nThe MBR-to-GPT conversion will leave at least one gap in the partition numbering if the orig‐\ninal MBR used logical partitions. These gaps are harmless, but you can eliminate them by us‐\ning the -s (--sort) option, if you like. (Doing this may require you to update your\n/etc/fstab file.)\n\nWhen creating a fresh partition table, certain considerations may be in order:\n\n\n* For data (non-boot) disks, and for boot disks used on BIOS-based computers with GRUB\nas the boot loader, partitions may be created in whatever order and in whatever sizes\nare desired.\n\n\n* Boot disks for EFI-based systems require an EFI System Partition (gdisk internal code\n0xEF00) formatted as FAT-32. I recommended making this partition 550 MiB. (Smaller\nESPs are common, but some EFIs have flaky FAT drivers that necessitate a larger parti‐\ntion for reliable operation.) Boot-related files are stored here. (Note that GNU\nParted identifies such partitions as having the \"boot flag\" set.)\n\n\n* Some boot loaders for BIOS-based systems make use of a BIOS Boot Partition (gdisk in‐\nternal code 0xEF02), in which the secondary boot loader is stored, possibly without\nthe benefit of a filesystem. (GRUB2 may optionally use such a partition.) This parti‐\ntion can typically be quite small (roughly 32 to 200 KiB, although 1 MiB is more com‐\nmon in practice), but you should consult your boot loader documentation for details.\n\n\n* If Windows is to boot from a GPT disk, a partition of type Microsoft Reserved (sgdisk\ninternal code 0x0C01) is recommended. This partition should be about 128 MiB in size.\nIt ordinarily follows the EFI System Partition and immediately precedes the Windows\ndata partitions. (Note that GNU Parted creates all FAT partitions as this type, which\nactually makes the partition unusable for normal file storage in both Windows and Mac\nOS X.)\n\n\n* Some OSes' GPT utilities create some blank space (typically 128 MiB) after each parti‐\ntion. The intent is to enable future disk utilities to use this space. Such free space\nis not required of GPT disks, but creating it may help in future disk maintenance.\n\n", "subsections": [] }, "OPTIONS": { "content": "Some options take no arguments, others take one argument (typically a partition number), and\nothers take compound arguments with colon delimitation. For instance, -n (--new) takes a par‐\ntition number, a starting sector number, and an ending sector number, as in sgdisk -n\n2:2000:50000 /dev/sdc, which creates a new partition, numbered 2, starting at sector 2000 an\nending at sector 50,000, on /dev/sdc.\n\nUnrelated options may be combined; however, some such combinations will be nonsense (such as\ndeleting a partition and then changing its GUID type code). sgdisk interprets options in the\norder in which they're entered, so effects can vary depending on order. For instance, sgdisk", "subsections": [ { "name": "-s -d 2", "content": "list; but sgdisk -d 2 -s deletes the original partition 2 and then sorts the modified parti‐\ntion table.\n\nError checking and opportunities to correct mistakes in sgdisk are minimal. Although the pro‐\ngram endeavors to keep the GPT data structures legal, it does not prompt for verification be‐\nfore performing its actions. Unless you require a command-line-driven program, you should use\nthe interactive gdisk instead of sgdisk, since gdisk allows you to quit without saving your\nchanges, should you make a mistake.\n\nAlthough sgdisk is based on the same partition-manipulation code as gdisk, sgdisk implements\nfewer features than its interactive sibling. Options available in sgdisk are:\n\n", "flag": "-d" }, { "name": "-a, --set-alignment=value", "content": "Set the sector alignment multiple. GPT fdisk aligns the start of partitions to sectors\nthat are multiples of this value, which defaults to 1 MiB (2048 on disks with 512-byte\nsectors) on freshly formatted disks. This alignment value is necessary to obtain opti‐\nmum performance with Western Digital Advanced Format and similar drives with larger\nphysical than logical sector sizes, with some types of RAID arrays, and with SSD de‐\nvices. When the -I option is used, this same alignment value is used to determine par‐\ntition end points; but partitions end at one less than a multiple of this value, to\nkeep the partition length a multiple of this value.\n\n", "flag": "-a", "long": "--set-alignment", "arg": "value" }, { "name": "-A, --attributes=list|[partnum:show|or|nand|xor|=|set|clear|toggle|get[:bitnum|hexbitmask]]", "content": "View or set partition attributes. Use list to see defined (known) attribute values.\nOmit the partition number (and even the device filename) when using this option. The\nothers require a partition number. The show and get options show the current attribute\nsettings (all attributes or for a particular bit, respectively). The or, nand, xor, =,\nset, clear, and toggle options enable you to change the attribute bit value. The set,\nclear, toggle, and get options work on a bit number; the others work on a hexadecimal\nbit mask. For example, type sgdisk -A 4:set:2 /dev/sdc to set the bit 2 attribute\n(legacy BIOS bootable) on partition 4 on /dev/sdc.\n\n", "flag": "-A", "long": "--attributes", "arg": "list|[partnum:show|or|nand|xor|=|set|clear|toggle|get[:bitnum|hexbitmask]]" }, { "name": "-b, --backup=file", "content": "Save partition data to a backup file. You can back up your current in-memory partition\ntable to a disk file using this option. The resulting file is a binary file consisting\nof the protective MBR, the main GPT header, the backup GPT header, and one copy of the\npartition table, in that order. Note that the backup is of the current in-memory data\nstructures, so if you launch the program, make changes, and then use this option, the\nbackup will reflect your changes. If the GPT data structures are damaged, the backup\nmay not accurately reflect the damaged state; instead, they will reflect GPT fdisk's\nfirst-pass interpretation of the GPT.\n\n", "flag": "-b", "long": "--backup", "arg": "file" }, { "name": "-B, --byte-swap-name=partnum", "content": "Swap the byte order for the name of the specified partition. Some partitioning tools,\nincluding GPT fdisk 1.0.7 and earlier, can write the partition name in the wrong byte\norder on big-endian computers, such as the IBM s390 mainframes and PowerPC-based Macs.\nThis feature corrects this problem.\n\n", "flag": "-B", "long": "--byte-swap-name", "arg": "partnum" }, { "name": "-c, --change-name=partnum:name", "content": "Change the GPT name of a partition. This name is encoded as a UTF-16 string, but\nproper entry and display of anything beyond basic ASCII values requires suitable lo‐\ncale and font support. For the most part, Linux ignores the partition name, but it may\nbe important in some OSes. If you want to set a name that includes a space, enclose it\nin quotation marks, as in sgdisk -c 1:\"Sample Name\" /dev/sdb. Note that the GPT name\nof a partition is distinct from the filesystem name, which is encoded in the filesys‐\ntem's data structures.\n\n", "flag": "-c", "long": "--change-name", "arg": "partnum:name" }, { "name": "-C, --recompute-chs", "content": "Recompute CHS values in protective or hybrid MBR. This option can sometimes help if a\ndisk utility, OS, or BIOS doesn't like the CHS values used by the partitions in the\nprotective or hybrid MBR. In particular, the GPT specification requires a CHS value of\n0xFFFFFF for over-8GiB partitions, but this value is technically illegal by the usual\nstandards. Some BIOSes hang if they encounter this value. This option will recompute a\nmore normal CHS value -- 0xFEFFFF for over-8GiB partitions, enabling these BIOSes to\nboot.\n\n", "flag": "-C", "long": "--recompute-chs" }, { "name": "-d, --delete=partnum", "content": "Delete a partition. This action deletes the entry from the partition table but does\nnot disturb the data within the sectors originally allocated to the partition on the\ndisk. If a corresponding hybrid MBR partition exists, gdisk deletes it, as well, and\nexpands any adjacent 0xEE (EFI GPT) MBR protective partition to fill the new free\nspace.\n\n", "flag": "-d", "long": "--delete", "arg": "partnum" }, { "name": "-D, --display-alignment", "content": "Display current sector alignment value. Partitions will be created on multiples of the\nsector value reported by this option. You can change the alignment value with the -a\noption.\n\n", "flag": "-D", "long": "--display-alignment" }, { "name": "-e, --move-second-header", "content": "Move backup GPT data structures to the end of the disk. Use this option if you've\nadded disks to a RAID array, thus creating a virtual disk with space that follows the\nbackup GPT data structures. This command moves the backup GPT data structures to the\nend of the disk, where they belong.\n\n", "flag": "-e", "long": "--move-second-header" }, { "name": "-E, --end-of-largest", "content": "Displays the sector number of the end of the largest available block of sectors on the\ndisk. A script may store this value and pass it back as part of -n's option to create\na partition. If no unallocated sectors are available, this function returns the value\n0.\n\n", "flag": "-E", "long": "--end-of-largest" }, { "name": "-f, --first-in-largest", "content": "Displays the sector number of the start of the largest available block of sectors on\nthe disk. A script may store this value and pass it back as part of -n's option to\ncreate a partition. If no unallocated sectors are available, this function returns the\nvalue 0. Note that this parameter is blind to partition alignment; when you actually\ncreate a partition, its start point might be changed from this value.\n\n", "flag": "-f", "long": "--first-in-largest" }, { "name": "-F, --first-aligned-in-largest", "content": "Similar to -f (--first-in-largest), except returns the sector number with the current\nalignment correction applied. Use this function if you need to compute the actual par‐\ntition start point rather than a theoretical start point or the actual start point if\nyou set the alignment value to 1.\n\n", "flag": "-F", "long": "--first-aligned-in-largest" }, { "name": "-g, --mbrtogpt", "content": "Convert an MBR or BSD disklabel disk to a GPT disk. As a safety measure, use of this\noption is required on MBR or BSD disklabel disks if you intend to save your changes,\nin order to prevent accidentally damaging such disks.\n\n", "flag": "-g", "long": "--mbrtogpt" }, { "name": "-G, --randomize-guids", "content": "Randomize the disk's GUID and all partitions' unique GUIDs (but not their partition\ntype code GUIDs). This function may be used after cloning a disk in order to render\nall GUIDs once again unique.\n\n", "flag": "-G", "long": "--randomize-guids" }, { "name": "-h, --hybrid", "content": "Create a hybrid MBR. This option takes from one to three partition numbers, separated\nby colons, as arguments. You may optionally specify a final partition \"EE\" to indicate\nthat the EFI GPT (type 0xEE) should be placed last in the table, otherwise it will be\nplaced first, followed by the partition(s) you specify. Their type codes are based on\nthe GPT fdisk type codes divided by 0x0100, which is usually correct for Windows par‐\ntitions. If the active/bootable flag should be set, you must do so in another program,\nsuch as fdisk. The gdisk program offers additional hybrid MBR creation options.\n\n", "flag": "-h", "long": "--hybrid" }, { "name": "-i, --info=partnum", "content": "Show detailed partition information. The summary information produced by the -p com‐\nmand necessarily omits many details, such as the partition's unique GUID and the\ntranslation of sgdisk's internal partition type code to a plain type name. The -i op‐\ntion displays this information for a single partition.\n\n", "flag": "-i", "long": "--info", "arg": "partnum" }, { "name": "-I, --align-end", "content": "When possible, align the end points of partitions to one less than a multiple of the\nalignment value. When both start and end points are aligned, partitions should be mul‐\ntiples of the alignment value in size, which is necessary for some partition encryp‐\ntion tools to function correctly. This option applies to all partitions created after\nthis option on the command line. Note that this alignment is not always possible; for\ninstance, if the free space at the end of a disk is less than the alignment value,\nwith the current final partition being aligned, and if sgdisk is asked to create a\npartition in that space, then it will not be end-aligned.\n\n", "flag": "-I", "long": "--align-end" }, { "name": "-j, --move-main-table=sector", "content": "Sets the start sector of the main partition table. This value is normally 2, but it\nmay need to be increased in some cases, such as when a system-on-chip (SoC) is\nhard-coded to read boot code from sector 2. I recommend against adjusting this value\nunless doing so is absolutely necessary.\n\n", "flag": "-j", "long": "--move-main-table", "arg": "sector" }, { "name": "-k, --move-backup-table=sector", "content": "Sets the start sector of the second/backup partition table. The backup table is usu‐\nally placed just before the last sector, which holds the backup header. The default\nvalue is thus the size of the disk, minus one, minus the total size of the partition\ntable (in sectors, usually 32). There are probably very few reasons to ever change\nthis, and while the EFI standard does not mandate it, most tooling assumes the backup\ntable to be at the very end of the disk.\n\n", "flag": "-k", "long": "--move-backup-table", "arg": "sector" }, { "name": "-l, --load-backup=file", "content": "Load partition data from a backup file. This option is the reverse of the -b option.\nNote that restoring partition data from anything but the original disk is not recom‐\nmended. This option will work even if the disk's original partition table is bad; how‐\never, most other options on the same command line will be ignored.\n\n", "flag": "-l", "long": "--load-backup", "arg": "file" }, { "name": "-L, --list-types", "content": "Display a summary of partition types. GPT uses a GUID to identify partition types for\nparticular OSes and purposes. For ease of data entry, sgdisk compresses these into\ntwo-byte (four-digit hexadecimal) values that are related to their equivalent MBR\ncodes. Specifically, the MBR code is multiplied by hexadecimal 0x0100. For instance,\nthe code for Linux swap space in MBR is 0x82, and it's 0x8200 in gdisk. A one-to-one\ncorrespondence is impossible, though. Most notably, the codes for all varieties of FAT\nand NTFS partition correspond to a single GPT code (entered as 0x0700 in sgdisk). Some\nOSes use a single MBR code but employ many more codes in GPT. For these, sgdisk adds\ncode numbers sequentially, such as 0xa500 for a FreeBSD disklabel, 0xa501 for FreeBSD\nboot, 0xa502 for FreeBSD swap, and so on. Note that these two-byte codes are unique to\ngdisk and sgdisk. This option does not require you to specify a valid disk device\nfilename.\n\n", "flag": "-L", "long": "--list-types" }, { "name": "-m, --gpttombr", "content": "Convert disk from GPT to MBR form. This option takes from one to four partition num‐\nbers, separated by colons, as arguments. Their type codes are based on the GPT fdisk\ntype codes divided by 0x0100. If the active/bootable flag should be set, you must do\nso in another program, such as fdisk. The gdisk program offers additional MBR conver‐\nsion options. It is not possible to convert more than four partitions from GPT to MBR\nform or to convert partitions that start above the 2TiB mark or that are larger than\n2TiB.\n\n", "flag": "-m", "long": "--gpttombr" }, { "name": "-n, --new=partnum:start:end", "content": "Create a new partition. You enter a partition number, starting sector, and an ending\nsector. Both start and end sectors can be specified in absolute terms as sector num‐\nbers or as positions measured in kibibytes (K), mebibytes (M), gibibytes (G),\ntebibytes (T), or pebibytes (P); for instance, 40M specifies a position 40MiB from the\nstart of the disk. You can specify locations relative to the start or end of the spec‐\nified default range by preceding the number by a '+' or '-' symbol, as in +2G to spec‐\nify a point 2GiB after the default start sector, or -200M to specify a point 200MiB\nbefore the last available sector. A start or end value of 0 specifies the default\nvalue, which is the start of the largest available block for the start sector and the\nend of the same block for the end sector. A partnum value of 0 causes the program to\nuse the first available partition number. Subsequent uses of the -A (--attributes), -c\n(--change-name), -t (--typecode), and -u (--partition-guid) options may also use 0 to\nrefer to the same partition.\n\n", "flag": "-n", "long": "--new", "arg": "partnum:start:end" }, { "name": "-N, --largest-new=num", "content": "Create a new partition that fills the largest available block of space on the disk.\nYou can use the -a (--set-alignment) option to adjust the alignment, if desired. A num\nvalue of 0 causes the program to use the first available partition number. Subsequent\nuses of the -A (--attributes), -c (--change-name), -t (--typecode), and -u (--parti‐\ntion-guid) options may also use 0 to refer to the same partition.\n\n", "flag": "-N", "long": "--largest-new", "arg": "num" }, { "name": "-o, --clear", "content": "Clear out all partition data. This includes GPT header data, all partition defini‐\ntions, and the protective MBR. Note that this operation will, like most other opera‐\ntions, fail on a damaged disk. If you want to prepare a disk you know to be damaged\nfor GPT use, you should first wipe it with -Z and then partition it normally. This op‐\ntion will work even if the disk's original partition table is bad; however, most other\noptions on the same command line will be ignored.\n\n", "flag": "-o", "long": "--clear" }, { "name": "-O, --print-mbr", "content": "Display basic MBR partition summary data. This includes partition numbers, starting\nand ending sector numbers, partition sizes, MBR partition types codes, and partition\nnames. This option is useful mainly for diagnosing partition table problems, particu‐\nlarly on disks with hybrid MBRs.\n\n", "flag": "-O", "long": "--print-mbr" }, { "name": "-p, --print", "content": "Display basic GPT partition summary data. This includes partition numbers, starting\nand ending sector numbers, partition sizes, sgdisk's partition types codes, and parti‐\ntion names. For additional information, use the -i (--info) option.\n\n", "flag": "-p", "long": "--print" }, { "name": "-P, --pretend", "content": "Pretend to make specified changes. In-memory GPT data structures are altered according\nto other parameters, but changes are not written to disk.\n\n", "flag": "-P", "long": "--pretend" }, { "name": "-r, --transpose", "content": "Swap two partitions' entries in the partition table. One or both partitions may be\nempty, although swapping two empty partitions is pointless. For instance, if parti‐\ntions 1-4 are defined, transposing 1 and 5 results in a table with partitions numbered\nfrom 2-5. Transposing partitions in this way has no effect on their disk space alloca‐\ntion; it only alters their order in the partition table.\n\n", "flag": "-r", "long": "--transpose" }, { "name": "-R, --replicate=second_device_filename", "content": "Replicate the main device's partition table on the specified second device. Note that\nthe replicated partition table is an exact copy, including all GUIDs; if the device\nshould have its own unique GUIDs, you should use the -G option on the new disk.\n\n", "flag": "-R", "long": "--replicate", "arg": "second_device_filename" }, { "name": "-s, --sort", "content": "Sort partition entries. GPT partition numbers need not match the order of partitions\non the disk. If you want them to match, you can use this option. Note that some par‐\ntitioning utilities sort partitions whenever they make changes. Such changes will be\nreflected in your device filenames, so you may need to edit /etc/fstab if you use this\noption.\n\n", "flag": "-s", "long": "--sort" }, { "name": "-t, --typecode=partnum:{hexcode|GUID}", "content": "Change a single partition's type code. You enter the type code using either a two-byte\nhexadecimal number, as described earlier, or a fully-specified GUID value, such as\nEBD0A0A2-B9E5-4433-87C0-68B6B72699C7.\n\n", "flag": "-t", "long": "--typecode", "arg": "partnum:{hexcode|GUID}" }, { "name": "-T, --transform-bsd=partnum", "content": "Transform BSD partitions into GPT partitions. This option works on BSD disklabels held\nwithin GPT (or converted MBR) partitions. Converted partitions' type codes are likely\nto need manual adjustment. sgdisk will attempt to convert BSD disklabels stored on the\nmain disk when launched, but this conversion is likely to produce first and/or last\npartitions that are unusable. The many BSD variants means that the probability of\nsgdisk being unable to convert a BSD disklabel is high compared to the likelihood of\nproblems with an MBR conversion.\n\n", "flag": "-T", "long": "--transform-bsd", "arg": "partnum" }, { "name": "-u, --partition-guid=partnum:guid", "content": "Set the partition unique GUID for an individual partition. The GUID may be a complete\nGUID or 'R' to set a random GUID.\n\n", "flag": "-u", "long": "--partition-guid", "arg": "partnum:guid" }, { "name": "-U, --disk-guid=guid", "content": "Set the GUID for the disk. The GUID may be a complete GUID or 'R' to set a random\nGUID.\n\n", "flag": "-U", "long": "--disk-guid", "arg": "guid" }, { "name": "--usage", "content": "Print a brief summary of available options.\n\n", "long": "--usage" }, { "name": "-v, --verify", "content": "Verify disk. This option checks for a variety of problems, such as incorrect CRCs and\nmismatched main and backup data. This option does not automatically correct most prob‐\nlems, though; for that, you must use options on the recovery & transformation menu. If\nno problems are found, this command displays a summary of unallocated disk space. This\noption will work even if the disk's original partition table is bad; however, most\nother options on the same command line will be ignored.\n\n", "flag": "-v", "long": "--verify" }, { "name": "-V, --version", "content": "Display program version information. This option may be used without specifying a de‐\nvice filename.\n\n", "flag": "-V", "long": "--version" }, { "name": "-z, --zap", "content": "Zap (destroy) the GPT data structures and then exit. Use this option if you want to\nrepartition a GPT disk using fdisk or some other GPT-unaware program. This option de‐\nstroys only the GPT data structures; it leaves the MBR intact. This makes it useful\nfor wiping out GPT data structures after a disk has been repartitioned for MBR using a\nGPT-unaware utility; however, there's a risk that it will damage boot loaders or even\nthe start of the first or end of the last MBR partition. If you use it on a valid GPT\ndisk, the MBR will be left with an inappropriate EFI GPT (0xEE) partition definition,\nwhich you can delete using another utility.\n\n", "flag": "-z", "long": "--zap" }, { "name": "-Z, --zap-all", "content": "Zap (destroy) the GPT and MBR data structures and then exit. This option works much\nlike -z, but as it wipes the MBR as well as the GPT, it's more suitable if you want to\nrepartition a disk after using this option, and completely unsuitable if you've al‐\nready repartitioned the disk.\n\n", "flag": "-Z", "long": "--zap-all" }, { "name": "-?, --help", "content": "Print a summary of options.\n\n", "flag": "-?", "long": "--help" } ] }, "RETURN VALUES": { "content": "sgdisk returns various values depending on its success or failure:\n\n\n0 Normal program execution\n\n\n1 Too few arguments\n\n\n2 An error occurred while reading the partition table\n\n\n3 Non-GPT disk detected and no -g option, but operation requires a write action\n\n\n4 An error prevented saving changes\n\n\n5 An error occurred while reading standard input (should never occur with sgdisk, but\nmay with gdisk)\n\n\n8 Disk replication operation (-R) failed\n\n", "subsections": [] }, "BUGS": { "content": "Known bugs and limitations include:\n\n\n* The program compiles correctly only on Linux, FreeBSD, and Mac OS X. Linux versions\nfor x86-64 (64-bit), x86 (32-bit), and PowerPC (32-bit) have been tested, with the\nx86-64 version having seen the most testing.\n\n\n* The FreeBSD version of the program can't write changes to the partition table to a\ndisk when existing partitions on that disk are mounted. (The same problem exists with\nmany other FreeBSD utilities, such as gpt, fdisk, and dd.) This limitation can be\novercome by typing sysctl kern.geom.debugflags=16 at a shell prompt.\n\n\n* The fields used to display the start and end sector numbers for partitions in the -p\noption are 14 characters wide. This translates to a limitation of about 45 PiB. On\nlarger disks, the displayed columns will go out of alignment.\n\n\n* The program can load only up to 128 partitions (4 primary partitions and 124 logical\npartitions) when converting from MBR format. This limit can be raised by changing the\n#define MAXMBRPARTS line in the basicmbr.h source code file and recompiling; how‐\never, such a change will require using a larger-than-normal partition table. (The\nlimit of 128 partitions was chosen because that number equals the 128 partitions sup‐\nported by the most common partition table size.)\n\n\n* Converting from MBR format sometimes fails because of insufficient space at the start\nor (more commonly) the end of the disk. Resizing the partition table (using the 's'\noption in the experts' menu) can sometimes overcome this problem; however, in extreme\ncases it may be necessary to resize a partition using GNU Parted or a similar tool\nprior to conversion with gdisk.\n\n\n* MBR conversions work only if the disk has correct LBA partition descriptors. These de‐\nscriptors should be present on any disk over 8 GiB in size or on smaller disks parti‐\ntioned with any but very ancient software.\n\n\n* BSD disklabel support can create first and/or last partitions that overlap with the\nGPT data structures. This can sometimes be compensated by adjusting the partition ta‐\nble size, but in extreme cases the affected partition(s) may need to be deleted.\n\n\n* Because of the highly variable nature of BSD disklabel structures, conversions from\nthis form may be unreliable -- partitions may be dropped, converted in a way that cre‐\nates overlaps with other partitions, or converted with incorrect start or end values.\nUse this feature with caution!\n\n\n* Booting after converting an MBR or BSD disklabel disk is likely to be disrupted. Some‐\ntimes re-installing a boot loader will fix the problem, but other times you may need\nto switch boot loaders. Except on EFI-based platforms, Windows through at least Win‐\ndows 7 RC doesn't support booting from GPT disks. Creating a hybrid MBR (using the 'h'\noption on the recovery & transformation menu) or abandoning GPT in favor of MBR may be\nyour only options in this case.\n\n", "subsections": [] }, "AUTHORS": { "content": "Primary author: Roderick W. Smith (rodsmith@rodsbooks.com)\n\nContributors:\n\n* Yves Blusseau (1otnwmz02@sneakemail.com)\n\n* David Hubbard (david.c.hubbard@gmail.com)\n\n* Justin Maggard (justin.maggard@netgear.com)\n\n* Dwight Schauer (das@teegra.net)\n\n* Florian Zumbiehl (florz@florz.de)\n\n\n", "subsections": [] }, "SEE ALSO": { "content": "cfdisk(8), cgdisk(8), fdisk(8), gdisk(8), mkfs(8), parted(8), sfdisk(8), fixparts(8).\n\nhttps://en.wikipedia.org/wiki/GUIDPartitionTable\n\nhttps://developer.apple.com/technotes/tn2006/tn2166.html\n\nhttps://www.rodsbooks.com/gdisk/\n\n", "subsections": [] }, "AVAILABILITY": { "content": "The sgdisk command is part of the GPT fdisk package and is available from Rod Smith.\n\nRoderick W. Smith 1.0.10 SGDISK(8)", "subsections": [] } }, "summary": "sgdisk - Command-line GUID partition table (GPT) manipulator for Linux and Unix", "flags": [ { "flag": "-d", "long": null, "arg": null, "description": "list; but sgdisk -d 2 -s deletes the original partition 2 and then sorts the modified parti‐ tion table. Error checking and opportunities to correct mistakes in sgdisk are minimal. Although the pro‐ gram endeavors to keep the GPT data structures legal, it does not prompt for verification be‐ fore performing its actions. Unless you require a command-line-driven program, you should use the interactive gdisk instead of sgdisk, since gdisk allows you to quit without saving your changes, should you make a mistake. Although sgdisk is based on the same partition-manipulation code as gdisk, sgdisk implements fewer features than its interactive sibling. Options available in sgdisk are:" }, { "flag": "-a", "long": "--set-alignment", "arg": "value", "description": "Set the sector alignment multiple. GPT fdisk aligns the start of partitions to sectors that are multiples of this value, which defaults to 1 MiB (2048 on disks with 512-byte sectors) on freshly formatted disks. This alignment value is necessary to obtain opti‐ mum performance with Western Digital Advanced Format and similar drives with larger physical than logical sector sizes, with some types of RAID arrays, and with SSD de‐ vices. When the -I option is used, this same alignment value is used to determine par‐ tition end points; but partitions end at one less than a multiple of this value, to keep the partition length a multiple of this value." }, { "flag": "-A", "long": "--attributes", "arg": "list|[partnum:show|or|nand|xor|=|set|clear|toggle|get[:bitnum|hexbitmask", "description": "View or set partition attributes. Use list to see defined (known) attribute values. Omit the partition number (and even the device filename) when using this option. The others require a partition number. The show and get options show the current attribute settings (all attributes or for a particular bit, respectively). The or, nand, xor, =, set, clear, and toggle options enable you to change the attribute bit value. The set, clear, toggle, and get options work on a bit number; the others work on a hexadecimal bit mask. For example, type sgdisk -A 4:set:2 /dev/sdc to set the bit 2 attribute (legacy BIOS bootable) on partition 4 on /dev/sdc." }, { "flag": "-b", "long": "--backup", "arg": "file", "description": "Save partition data to a backup file. You can back up your current in-memory partition table to a disk file using this option. The resulting file is a binary file consisting of the protective MBR, the main GPT header, the backup GPT header, and one copy of the partition table, in that order. Note that the backup is of the current in-memory data structures, so if you launch the program, make changes, and then use this option, the backup will reflect your changes. If the GPT data structures are damaged, the backup may not accurately reflect the damaged state; instead, they will reflect GPT fdisk's first-pass interpretation of the GPT." }, { "flag": "-B", "long": "--byte-swap-name", "arg": "partnum", "description": "Swap the byte order for the name of the specified partition. Some partitioning tools, including GPT fdisk 1.0.7 and earlier, can write the partition name in the wrong byte order on big-endian computers, such as the IBM s390 mainframes and PowerPC-based Macs. This feature corrects this problem." }, { "flag": "-c", "long": "--change-name", "arg": "partnum:name", "description": "Change the GPT name of a partition. This name is encoded as a UTF-16 string, but proper entry and display of anything beyond basic ASCII values requires suitable lo‐ cale and font support. For the most part, Linux ignores the partition name, but it may be important in some OSes. If you want to set a name that includes a space, enclose it in quotation marks, as in sgdisk -c 1:\"Sample Name\" /dev/sdb. Note that the GPT name of a partition is distinct from the filesystem name, which is encoded in the filesys‐ tem's data structures." }, { "flag": "-C", "long": "--recompute-chs", "arg": null, "description": "Recompute CHS values in protective or hybrid MBR. This option can sometimes help if a disk utility, OS, or BIOS doesn't like the CHS values used by the partitions in the protective or hybrid MBR. In particular, the GPT specification requires a CHS value of 0xFFFFFF for over-8GiB partitions, but this value is technically illegal by the usual standards. Some BIOSes hang if they encounter this value. This option will recompute a more normal CHS value -- 0xFEFFFF for over-8GiB partitions, enabling these BIOSes to boot." }, { "flag": "-d", "long": "--delete", "arg": "partnum", "description": "Delete a partition. This action deletes the entry from the partition table but does not disturb the data within the sectors originally allocated to the partition on the disk. If a corresponding hybrid MBR partition exists, gdisk deletes it, as well, and expands any adjacent 0xEE (EFI GPT) MBR protective partition to fill the new free space." }, { "flag": "-D", "long": "--display-alignment", "arg": null, "description": "Display current sector alignment value. Partitions will be created on multiples of the sector value reported by this option. You can change the alignment value with the -a option." }, { "flag": "-e", "long": "--move-second-header", "arg": null, "description": "Move backup GPT data structures to the end of the disk. Use this option if you've added disks to a RAID array, thus creating a virtual disk with space that follows the backup GPT data structures. This command moves the backup GPT data structures to the end of the disk, where they belong." }, { "flag": "-E", "long": "--end-of-largest", "arg": null, "description": "Displays the sector number of the end of the largest available block of sectors on the disk. A script may store this value and pass it back as part of -n's option to create a partition. If no unallocated sectors are available, this function returns the value 0." }, { "flag": "-f", "long": "--first-in-largest", "arg": null, "description": "Displays the sector number of the start of the largest available block of sectors on the disk. A script may store this value and pass it back as part of -n's option to create a partition. If no unallocated sectors are available, this function returns the value 0. Note that this parameter is blind to partition alignment; when you actually create a partition, its start point might be changed from this value." }, { "flag": "-F", "long": "--first-aligned-in-largest", "arg": null, "description": "Similar to -f (--first-in-largest), except returns the sector number with the current alignment correction applied. Use this function if you need to compute the actual par‐ tition start point rather than a theoretical start point or the actual start point if you set the alignment value to 1." }, { "flag": "-g", "long": "--mbrtogpt", "arg": null, "description": "Convert an MBR or BSD disklabel disk to a GPT disk. As a safety measure, use of this option is required on MBR or BSD disklabel disks if you intend to save your changes, in order to prevent accidentally damaging such disks." }, { "flag": "-G", "long": "--randomize-guids", "arg": null, "description": "Randomize the disk's GUID and all partitions' unique GUIDs (but not their partition type code GUIDs). This function may be used after cloning a disk in order to render all GUIDs once again unique." }, { "flag": "-h", "long": "--hybrid", "arg": null, "description": "Create a hybrid MBR. This option takes from one to three partition numbers, separated by colons, as arguments. You may optionally specify a final partition \"EE\" to indicate that the EFI GPT (type 0xEE) should be placed last in the table, otherwise it will be placed first, followed by the partition(s) you specify. Their type codes are based on the GPT fdisk type codes divided by 0x0100, which is usually correct for Windows par‐ titions. If the active/bootable flag should be set, you must do so in another program, such as fdisk. The gdisk program offers additional hybrid MBR creation options." }, { "flag": "-i", "long": "--info", "arg": "partnum", "description": "Show detailed partition information. The summary information produced by the -p com‐ mand necessarily omits many details, such as the partition's unique GUID and the translation of sgdisk's internal partition type code to a plain type name. The -i op‐ tion displays this information for a single partition." }, { "flag": "-I", "long": "--align-end", "arg": null, "description": "When possible, align the end points of partitions to one less than a multiple of the alignment value. When both start and end points are aligned, partitions should be mul‐ tiples of the alignment value in size, which is necessary for some partition encryp‐ tion tools to function correctly. This option applies to all partitions created after this option on the command line. Note that this alignment is not always possible; for instance, if the free space at the end of a disk is less than the alignment value, with the current final partition being aligned, and if sgdisk is asked to create a partition in that space, then it will not be end-aligned." }, { "flag": "-j", "long": "--move-main-table", "arg": "sector", "description": "Sets the start sector of the main partition table. This value is normally 2, but it may need to be increased in some cases, such as when a system-on-chip (SoC) is hard-coded to read boot code from sector 2. I recommend against adjusting this value unless doing so is absolutely necessary." }, { "flag": "-k", "long": "--move-backup-table", "arg": "sector", "description": "Sets the start sector of the second/backup partition table. The backup table is usu‐ ally placed just before the last sector, which holds the backup header. The default value is thus the size of the disk, minus one, minus the total size of the partition table (in sectors, usually 32). There are probably very few reasons to ever change this, and while the EFI standard does not mandate it, most tooling assumes the backup table to be at the very end of the disk." }, { "flag": "-l", "long": "--load-backup", "arg": "file", "description": "Load partition data from a backup file. This option is the reverse of the -b option. Note that restoring partition data from anything but the original disk is not recom‐ mended. This option will work even if the disk's original partition table is bad; how‐ ever, most other options on the same command line will be ignored." }, { "flag": "-L", "long": "--list-types", "arg": null, "description": "Display a summary of partition types. GPT uses a GUID to identify partition types for particular OSes and purposes. For ease of data entry, sgdisk compresses these into two-byte (four-digit hexadecimal) values that are related to their equivalent MBR codes. Specifically, the MBR code is multiplied by hexadecimal 0x0100. For instance, the code for Linux swap space in MBR is 0x82, and it's 0x8200 in gdisk. A one-to-one correspondence is impossible, though. Most notably, the codes for all varieties of FAT and NTFS partition correspond to a single GPT code (entered as 0x0700 in sgdisk). Some OSes use a single MBR code but employ many more codes in GPT. For these, sgdisk adds code numbers sequentially, such as 0xa500 for a FreeBSD disklabel, 0xa501 for FreeBSD boot, 0xa502 for FreeBSD swap, and so on. Note that these two-byte codes are unique to gdisk and sgdisk. This option does not require you to specify a valid disk device filename." }, { "flag": "-m", "long": "--gpttombr", "arg": null, "description": "Convert disk from GPT to MBR form. This option takes from one to four partition num‐ bers, separated by colons, as arguments. Their type codes are based on the GPT fdisk type codes divided by 0x0100. If the active/bootable flag should be set, you must do so in another program, such as fdisk. The gdisk program offers additional MBR conver‐ sion options. It is not possible to convert more than four partitions from GPT to MBR form or to convert partitions that start above the 2TiB mark or that are larger than 2TiB." }, { "flag": "-n", "long": "--new", "arg": "partnum:start:end", "description": "Create a new partition. You enter a partition number, starting sector, and an ending sector. Both start and end sectors can be specified in absolute terms as sector num‐ bers or as positions measured in kibibytes (K), mebibytes (M), gibibytes (G), tebibytes (T), or pebibytes (P); for instance, 40M specifies a position 40MiB from the start of the disk. You can specify locations relative to the start or end of the spec‐ ified default range by preceding the number by a '+' or '-' symbol, as in +2G to spec‐ ify a point 2GiB after the default start sector, or -200M to specify a point 200MiB before the last available sector. A start or end value of 0 specifies the default value, which is the start of the largest available block for the start sector and the end of the same block for the end sector. A partnum value of 0 causes the program to use the first available partition number. Subsequent uses of the -A (--attributes), -c (--change-name), -t (--typecode), and -u (--partition-guid) options may also use 0 to refer to the same partition." }, { "flag": "-N", "long": "--largest-new", "arg": "num", "description": "Create a new partition that fills the largest available block of space on the disk. You can use the -a (--set-alignment) option to adjust the alignment, if desired. A num value of 0 causes the program to use the first available partition number. Subsequent uses of the -A (--attributes), -c (--change-name), -t (--typecode), and -u (--parti‐ tion-guid) options may also use 0 to refer to the same partition." }, { "flag": "-o", "long": "--clear", "arg": null, "description": "Clear out all partition data. This includes GPT header data, all partition defini‐ tions, and the protective MBR. Note that this operation will, like most other opera‐ tions, fail on a damaged disk. If you want to prepare a disk you know to be damaged for GPT use, you should first wipe it with -Z and then partition it normally. This op‐ tion will work even if the disk's original partition table is bad; however, most other options on the same command line will be ignored." }, { "flag": "-O", "long": "--print-mbr", "arg": null, "description": "Display basic MBR partition summary data. This includes partition numbers, starting and ending sector numbers, partition sizes, MBR partition types codes, and partition names. This option is useful mainly for diagnosing partition table problems, particu‐ larly on disks with hybrid MBRs." }, { "flag": "-p", "long": "--print", "arg": null, "description": "Display basic GPT partition summary data. This includes partition numbers, starting and ending sector numbers, partition sizes, sgdisk's partition types codes, and parti‐ tion names. For additional information, use the -i (--info) option." }, { "flag": "-P", "long": "--pretend", "arg": null, "description": "Pretend to make specified changes. In-memory GPT data structures are altered according to other parameters, but changes are not written to disk." }, { "flag": "-r", "long": "--transpose", "arg": null, "description": "Swap two partitions' entries in the partition table. One or both partitions may be empty, although swapping two empty partitions is pointless. For instance, if parti‐ tions 1-4 are defined, transposing 1 and 5 results in a table with partitions numbered from 2-5. Transposing partitions in this way has no effect on their disk space alloca‐ tion; it only alters their order in the partition table." }, { "flag": "-R", "long": "--replicate", "arg": "second_device_filename", "description": "Replicate the main device's partition table on the specified second device. Note that the replicated partition table is an exact copy, including all GUIDs; if the device should have its own unique GUIDs, you should use the -G option on the new disk." }, { "flag": "-s", "long": "--sort", "arg": null, "description": "Sort partition entries. GPT partition numbers need not match the order of partitions on the disk. If you want them to match, you can use this option. Note that some par‐ titioning utilities sort partitions whenever they make changes. Such changes will be reflected in your device filenames, so you may need to edit /etc/fstab if you use this option." }, { "flag": "-t", "long": "--typecode", "arg": "partnum:{hexcode|GUID}", "description": "Change a single partition's type code. You enter the type code using either a two-byte hexadecimal number, as described earlier, or a fully-specified GUID value, such as EBD0A0A2-B9E5-4433-87C0-68B6B72699C7." }, { "flag": "-T", "long": "--transform-bsd", "arg": "partnum", "description": "Transform BSD partitions into GPT partitions. This option works on BSD disklabels held within GPT (or converted MBR) partitions. Converted partitions' type codes are likely to need manual adjustment. sgdisk will attempt to convert BSD disklabels stored on the main disk when launched, but this conversion is likely to produce first and/or last partitions that are unusable. The many BSD variants means that the probability of sgdisk being unable to convert a BSD disklabel is high compared to the likelihood of problems with an MBR conversion." }, { "flag": "-u", "long": "--partition-guid", "arg": "partnum:guid", "description": "Set the partition unique GUID for an individual partition. The GUID may be a complete GUID or 'R' to set a random GUID." }, { "flag": "-U", "long": "--disk-guid", "arg": "guid", "description": "Set the GUID for the disk. The GUID may be a complete GUID or 'R' to set a random GUID." }, { "flag": "", "long": "--usage", "arg": null, "description": "Print a brief summary of available options." }, { "flag": "-v", "long": "--verify", "arg": null, "description": "Verify disk. This option checks for a variety of problems, such as incorrect CRCs and mismatched main and backup data. This option does not automatically correct most prob‐ lems, though; for that, you must use options on the recovery & transformation menu. If no problems are found, this command displays a summary of unallocated disk space. This option will work even if the disk's original partition table is bad; however, most other options on the same command line will be ignored." }, { "flag": "-V", "long": "--version", "arg": null, "description": "Display program version information. This option may be used without specifying a de‐ vice filename." }, { "flag": "-z", "long": "--zap", "arg": null, "description": "Zap (destroy) the GPT data structures and then exit. Use this option if you want to repartition a GPT disk using fdisk or some other GPT-unaware program. This option de‐ stroys only the GPT data structures; it leaves the MBR intact. This makes it useful for wiping out GPT data structures after a disk has been repartitioned for MBR using a GPT-unaware utility; however, there's a risk that it will damage boot loaders or even the start of the first or end of the last MBR partition. If you use it on a valid GPT disk, the MBR will be left with an inappropriate EFI GPT (0xEE) partition definition, which you can delete using another utility." }, { "flag": "-Z", "long": "--zap-all", "arg": null, "description": "Zap (destroy) the GPT and MBR data structures and then exit. This option works much like -z, but as it wipes the MBR as well as the GPT, it's more suitable if you want to repartition a disk after using this option, and completely unsuitable if you've al‐ ready repartitioned the disk." }, { "flag": "-?", "long": "--help", "arg": null, "description": "Print a summary of options." } ], "examples": [], "see_also": [ { "name": "cfdisk", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/cfdisk/8/json" }, { "name": "cgdisk", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/cgdisk/8/json" }, { "name": "fdisk", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/fdisk/8/json" }, { "name": "gdisk", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/gdisk/8/json" }, { "name": "mkfs", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/mkfs/8/json" }, { "name": "parted", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/parted/8/json" }, { "name": "sfdisk", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/sfdisk/8/json" }, { "name": "fixparts", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/fixparts/8/json" } ] }