fdisk [options] device
fdisk -l [device …]
Interactive program for Creation and manipulation of partition tables (noninteractive version).
Block devices (Disks, RAM drive) can be divided into one or more logical disks called partitions, recorded in the partition table, usually found in sector 0 of the disk and duplicated elsewhere. (Aka `disk slices' and a `disklabel'.)
First, last, sectors and sizes can be specified by the +
m print this menu, i information about a partition Command (m for help): i Partition number (1-3, default 3): 3 Device: /dev/mmcblk0p3 Start: 31117312 End: 62333951 Sectors: 31216640 Cylinders: 487761 Size: 14.9G Id: 83 Type: Linux Start-C/H/S: 832/0/1 End-C/H/S: 143/3/16 p print Disk /dev/mmcblk0: 29.7 GiB, 31914983424 bytes, 62333952 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: dos Disk identifier: 0xc5b4c492 Device Boot Start End Sectors Size Id Type /dev/mmcblk0p1 8192 93236 85045 41.5M c W95 FAT32 (LBA) /dev/mmcblk0p2 94208 31116287 31022080 14.8G 83 Linux /dev/mmcblk0p3 31117312 62333951 31216640 14.9G 83 Linux v verify Remaining 1995 unallocated 512-byte sectors. F list free space, Unpartitioned space /dev/mmcblk0: 3 MiB, 3145728 bytes, 6144 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes Start End Sectors Size 2048 8191 6144 3M n add new
t change type
l list known types0 Empty 24 NEC DOS 81 Minix / old Lin bf Solaris 1 FAT12 27 Hidden NTFS Win 82 Linux swap / So c1 DRDOS/sec (FAT- 2 XENIX root 39 Plan 9 83 Linux c4 DRDOS/sec (FAT- 3 XENIX usr 3c PartitionMagic 84 OS/2 hidden or c6 DRDOS/sec (FAT- 4 FAT16 <32M 40 Venix 80286 85 Linux extended c7 Syrinx 5 Extended 41 PPC PReP Boot 86 NTFS volume set da Non-FS data 6 FAT16 42 SFS 87 NTFS volume set db CP/M / CTOS / . 7 HPFS/NTFS/exFAT 4d QNX4.x 88 Linux plaintext de Dell Utility 8 AIX 4e QNX4.x 2nd part 8e Linux LVM df BootIt 9 AIX bootable 4f QNX4.x 3rd part 93 Amoeba e1 DOS access a OS/2 Boot Manag 50 OnTrack DM 94 Amoeba BBT e3 DOS R/O b W95 FAT32 51 OnTrack DM6 Aux 9f BSD/OS e4 SpeedStor c W95 FAT32 (LBA) 52 CP/M a0 IBM Thinkpad hi ea Rufus alignment e W95 FAT16 (LBA) 53 OnTrack DM6 Aux a5 FreeBSD eb BeOS fs f W95 Ext'd (LBA) 54 OnTrackDM6 a6 OpenBSD ee GPT 10 OPUS 55 EZ-Drive a7 NeXTSTEP ef EFI (FAT-12/16/ 11 Hidden FAT12 56 Golden Bow a8 Darwin UFS f0 Linux/PA-RISC b 12 Compaq diagnost 5c Priam Edisk a9 NetBSD f1 SpeedStor 14 Hidden FAT16 <3 61 SpeedStor ab Darwin boot f4 SpeedStor 16 Hidden FAT16 63 GNU HURD or Sys af HFS / HFS+ f2 DOS secondary 17 Hidden HPFS/NTF 64 Novell Netware b7 BSDI fs fb VMware VMFS 18 AST SmartSleep 65 Novell Netware b8 BSDI swap fc VMware VMKCORE 1b Hidden W95 FAT3 70 DiskSecure Mult bb Boot Wizard hid fd Linux raid auto 1c Hidden W95 FAT3 75 PC/IX bc Acronis FAT32 L fe LANstep 1e Hidden W95 FAT1 80 Old Minix be Solaris boot ff BBTu change display/entry units w write table to disk and exit q quit without saving changes Create a new label: g GPT, G SGI (IRIX) , o DOS , s Sun O output sfdisk script, I input script DOS (MBR Master BOot Record): a toggle a bootable flag, b edit nested BSD disklabel, c toggle the dos compatibility flag x extra functionality (experts only) DOS (MBR) b move beginning of data in a partition, i change the disk identifier d print the raw data of the first sector from the device D print the raw data of the disklabel from the device f fix partitions order c change number of cylinders, h change number of heads, s change number of sectors/track bad ideas
/dev/sda. refers to the entire disk.
partition is a device name followed by a partition number. For example,
/dev/sda1 is the first partition on the first hard disk
The "last sector" accepts size specified by number of sectors or by
If the size is prefixed by '+' it is interpreted as relative to the partition first sector in bytes, unless . followed by the suffixes K==KB==KiB=1024, M==MB==MiB=1024*1024,…
Icommand) sfdisk script files. These are applied to in-memory partition table. allowing modifification before write it using command 'O'.
GPT(GUID Partition Table) the modern standard for the layout of the partition table. The first sector is reserved for a protective MBR. GPT is always a better choice than MBR, especially on modern hardware with a UEFI boot loader.
MBRA DOS-type partition table. There are 4 primary partitions. One may be an extended partition; this is a container holding logical partitions. The four primary partitions are numbered 1-4. Logical partitions always start with 5.
fdisk [-afiuvBFS] [-0 | -1 | -2 | -3]
[-t disktab] [-T disktype] [-E number] [-b cylinders|heads|sectors]
[-s id/start/size[/bootmenu]] [-c bootcode] [-r|w file] [device]
if sector 0 is not valid a boot sector. fdisk initialises the boot code as well as the partition table, all four partitions will be marked empty.
-u are used to indicate that the partition data is to be updated.
fdisk program will enter an interactive conversational mode.
fdisk will calculate the correct
sector values for
any partition you edit. If you specify
-v you will be asked whether you
want to specify them
When all the data for the first sector has been accumulated,
fdisk will ask if you really want to write the new partition table. Only
if you reply affirmatively to this question will
fdisk write anything to the disk.
|Update partition slot 0. |
| Update partition slot 1. |
| Update partition slot 2. |
| Update partition slot 3. |
| Change the active partition. In interactive mode this question
will be asked after the partitions have been processed.
Specify the BIOS parameters for |
|On an i386 or amd64 system, interactively update the boot selec-
tor settings. (The boot selector permits the user to interac-
tively select the boot partition, and thus which operating system
is run, at system boot time. See mbr(8) for more information.)
Specify the filename that |
Update extended partition |
| Run |
|Indicate that |
| Explicitly request initialisation of the master boot code (simi-
lar to what |
| Lists known |
Read the boot record from file |
Specify the partition |
| When used with no other flags print a series of |
Disk: /dev/rwd0d NetBSD disklabel disk geometry: cylinders: 16383, heads: 16, sectors/track: 63 (1008 sectors/cylinder) total sectors: 40032696 BIOS disk geometry: cylinders: 1023, heads: 255, sectors/track: 63 (16065 sectors/cylinder) total sectors: 40032696 Partition table: 0: NetBSD (sysid 169) bootmenu: net 1.5. start 4209030, size 8289540 (4048 MB, Cyls 262-778), Active 1: Primary DOS with 32 bit FAT (sysid 11) bootmenu: win98 start 63, size 4208967 (2055 MB, Cyls 0-262) 2: NetBSD (sysid 169) bootmenu: current start 32515560, size 7517136 (3670 MB, Cyls 2024-2491/234/40) 3: Ext. partition - LBA (sysid 15) start 12498570, size 20016990 (9774 MB, Cyls 778-2024) Extended partition table: E0: NetBSD (sysid 169) bootmenu: test start 12498633, size 12305727 (6009 MB, Cyls 778-1544) E1: Primary DOS with 32 bit FAT (sysid 11) start 24804423, size 4096512 (2000 MB, Cyls 1544-1799) E2: Primary DOS with 32 bit FAT (sysid 11) start 28900998, size 3614562 (1765 MB, Cyls 1799-2024) Bootselector enabled, infinite timeout.This example disk is divided into four partitions the last of which is an extended partition. The sub-partitions of the extended partition are also shown. In this case there is no free space in either the disk or in the extended partition.
The various fields in each partition entry are:
MB MB, Cyls
next) [, Active]
is the number of the partition.
id_name is the name of the filesystem type or operating system that
uses this partition.
is the number that identifies the partition type.
15 to an extended partition and 0 to mark a partition as unused. Use
list the known partition types.
bootmenu is the menu prompt output by the interactive boot code for this
partition. This line is omitted if the prompt is not defined.
are the start address and size of the partition in sectors.
MB is the size of the partition in megabytes.
are the bounds of this partition displayed as cylin-
der/head/sector. If the partition starts (or ends) on a cylin-
der boundary the head and sector values are omitted. If
not specified the start of extended partitions and the first
partition on the disk are rounded down to include the mandatory
red tape in the preceding track.
Active is output if this is the active partition.
-v two additional lines are output for each partition:
are the beginning or ending address of a partition.
Note: these numbers are read from the bootblock, so are the
values calculated by a previous run of
file to write the output to a
file and later specify
file to read back .
This can be done without having write access to the disk volume.
The word `partition' is used to mean both an MBR partition and a NetBSD
partition, sometimes in the same sentence.
There are subtleties that the program detects that are not explained in this manual page.