+++ /dev/null
-.\" Copyright 1992, 1993 Rickard E. Faith (faith@cs.unc.edu)
-.\" Copyright 1998 Andries E. Brouwer (aeb@cwi.nl)
-.\" Copyright 2012 Davidlohr Bueso <dave@gnu.org>
-.\" Copyright (C) 2013 Karel Zak <kzak@redhat.com>
-.\" May be distributed under the GNU General Public License
-.TH FDISK 8 "February 2016" "util-linux" "System Administration"
-
-.SH NAME
-fdisk \- manipulate disk partition table
-
-.SH SYNOPSIS
-.B fdisk
-[options]
-.I device
-.sp
-.B fdisk \-l
-.RI [ device ...]
-
-.SH DESCRIPTION
-.B fdisk
-is a dialog-driven program for creation and manipulation of partition tables.
-It understands GPT, MBR, Sun, SGI and BSD partition tables.
-
-Block devices can be divided into one or more logical disks called
-.IR partitions .
-This division is recorded in the
-.IR "partition table" ,
-usually found in sector 0 of the disk.
-(In the BSD world one talks about `disk slices' and a `disklabel'.)
-
-All partitioning is driven by device I/O limits (the topology) by default.
-.B fdisk
-is able to optimize the disk layout for a 4K-sector size and use an alignment offset on
-modern devices for MBR and GPT. It is always a good idea to follow \fBfdisk\fR's defaults
-as the default values (e.g., first and last partition sectors) and partition
-sizes specified by the +/-<size>{M,G,...} notation are always aligned according
-to the device properties.
-
-CHS (Cylinder-Head-Sector) addressing is deprecated and not used by default.
-Please, do not follow old articles and recommendations with "fdisk \-S <n> \-H
-<n>" advices for SSD or 4K-sector devices.
-
-Note that
-.BR partx (8)
-provides a rich interface for scripts to print disk layouts,
-.B fdisk
-is mostly designed for humans. Backward compatibility in the output of
-.B fdisk
-is not guaranteed. The input (the commands) should always be backward compatible.
-
-.SH OPTIONS
-.TP
-\fB\-b\fR, \fB\-\-sector\-size\fR \fIsectorsize\fP
-Specify the sector size of the disk. Valid values are 512, 1024, 2048, and 4096.
-(Recent kernels know the sector size. Use this option only on old kernels or
-to override the kernel's ideas.) Since util-linux-2.17, \fBfdisk\fR differentiates
-between logical and physical sector size. This option changes both sector sizes to
-.IB sectorsize .
-.TP
-\fB\-B\fR, \fB\-\-protect\-boot\fP
-Don't erase the begin of the first disk sector when create a new disk label. This
-feature is supported for GPT and MBR.
-.TP
-\fB\-c\fR, \fB\-\-compatibility\fR[=\fImode\fR]
-Specify the compatibility mode, 'dos' or 'nondos'. The default is non-DOS
-mode. For backward compatibility, it is possible to use the option without
-the \fImode\fR argument -- then the default is used. Note that the optional
-\fImode\fR argument cannot be separated from the \fB\-c\fR option by a space,
-the correct form is for example '\-c=dos'.
-.TP
-\fB\-h\fR, \fB\-\-help\fR
-Display a help text and exit.
-.TP
-\fB\-L\fR, \fB\-\-color\fR[=\fIwhen\fR]
-Colorize the output. The optional argument \fIwhen\fP
-can be \fBauto\fR, \fBnever\fR or \fBalways\fR. If the \fIwhen\fR argument is omitted,
-it defaults to \fBauto\fR. The colors can be disabled; for the current built-in default
-see the \fB\-\-help\fR output. See also the \fBCOLORS\fR section.
-.TP
-\fB\-l\fR, \fB\-\-list\fR
-List the partition tables for the specified devices and then exit.
-If no devices are given, those mentioned in
-.I /proc/partitions
-(if that file exists) are used.
-.TP
-.BR \-o , " \-\-output " \fIlist\fP
-Specify which output columns to print. Use
-.B \-\-help
-to get a list of all supported columns.
-
-The default list of columns may be extended if \fIlist\fP is
-specified in the format \fI+list\fP (e.g., \fB\-o +UUID\fP).
-.TP
-\fB\-s\fR, \fB\-\-getsz\fR
-Print the size in 512-byte sectors of each given block device. This option is DEPRECATED
-in favour of
-.BR blockdev (8).
-.TP
-\fB\-t\fR, \fB\-\-type\fR \fItype\fR
-Enable support only for disklabels of the specified \fItype\fP, and disable
-support for all other types.
-.TP
-\fB\-u\fR, \fB\-\-units\fR[=\fIunit\fR]
-When listing partition tables, show sizes in 'sectors' or in 'cylinders'. The
-default is to show sizes in sectors. For backward compatibility, it is possible
-to use the option without the \fIunit\fR argument -- then the default is used.
-Note that the optional \fIunit\fR argument cannot be separated from the \fB\-u\fR
-option by a space, the correct form is for example '\-u=cylinders'.
-
-.TP
-\fB\-C\fR, \fB\-\-cylinders\fR \fInumber\fR
-Specify the number of cylinders of the disk.
-I have no idea why anybody would want to do so.
-.TP
-\fB\-H\fR, \fB\-\-heads\fR \fInumber\fR
-Specify the number of heads of the disk. (Not the physical number,
-of course, but the number used for partition tables.)
-Reasonable values are 255 and 16.
-.TP
-\fB\-S\fR, \fB\-\-sectors\fR \fInumber\fR
-Specify the number of sectors per track of the disk.
-(Not the physical number, of course, but the number used for
-partition tables.) A reasonable value is 63.
-
-.TP
-\fB\-w\fR, \fB\-\-wipe\fR \fIwhen\fR
-Wipe filesystem, RAID and partition-table signatures from the device, in order
-to avoid possible collisions. The argument \fIwhen\fR can be \fBauto\fR,
-\fBnever\fR or \fBalways\fR. When this option is not given, the default is
-\fBauto\fR, in which case signatures are wiped only when in interactive mode.
-In all cases detected signatures are reported by warning messages
-before a new partition table is created. See also
-.BR wipefs (8)
-command.
-
-.TP
-\fB\-W\fR, \fB\-\-wipe-partition\fR \fIwhen\fR
-Wipe filesystem, RAID and partition-table signatures from a newly created
-partitions, in order to avoid possible collisions. The argument \fIwhen\fR can
-be \fBauto\fR, \fBnever\fR or \fBalways\fR. When this option is not given, the
-default is \fBauto\fR, in which case signatures are wiped only when in
-interactive mode and after confirmation by user. In all cases detected
-signatures are reported by warning messages before a new partition is
-created. See also
-.BR wipefs (8)
-command.
-
-.TP
-\fB\-V\fR, \fB\-\-version\fR
-Display version information and exit.
-
-.SH DEVICES
-The
-.I device
-is usually /dev/sda, /dev/sdb or so. A device name refers to the entire disk.
-Old systems without libata (a library used inside the Linux kernel to support
-ATA host controllers and devices) make a difference between IDE and SCSI disks.
-In such cases the device name will be /dev/hd* (IDE) or /dev/sd* (SCSI).
-
-The
-.I partition
-is a device name followed by a partition number. For example, /dev/sda1 is the
-first partition on the first hard disk in the system. See also Linux kernel
-documentation (the Documentation/devices.txt file).
-
-.SH SIZES
-The "last sector" dialog accepts partition size specified by number of sectors
-or by +/-<size>{K,B,M,G,...} notation.
-
-If the size is prefixed by '+' then it is interpreted as relative to the
-partition first sector. If the size is prefixed by '\-' then it is interpreted
-as relative to the high limit (last available sector for the partition).
-
-In the case the size is specified in bytes than the number may be followed by
-the multiplicative suffixes KiB=1024, MiB=1024*1024, and so on for GiB, TiB,
-PiB, EiB, ZiB and YiB. The "iB" is optional, e.g., "K" has the same meaning as
-"KiB".
-
-The relative sizes are always aligned according to device I/O limits. The
-+/-<size>{K,B,M,G,...} notation is recommended.
-
-For backward compatibility fdisk also accepts the suffixes KB=1000,
-MB=1000*1000, and so on for GB, TB, PB, EB, ZB and YB. These 10^N suffixes
-are deprecated.
-
-.SH SCRIPT FILES
-.B fdisk
-allows to read (by 'I' command) sfdisk compatible script files. The script is
-applied to in-memory partition table, and then it is possible to modify the
-partition table before you write it to the device.
-.PP
-And vice-versa it is possible to write the current in-memory disk layout
-to the script file by command 'O'.
-.PP
-The script files are compatible between cfdisk, sfdisk, fdisk and another
-libfdisk applications. For more details see
-.BR sfdisk (8).
-
-.SH DISK LABELS
-.B GPT (GUID Partition Table)
-.RS
-GPT is modern standard for the layout of the partition table. GPT uses 64-bit
-logical block addresses, checksums, UUIDs and names for partitions and an
-unlimited number of partitions (although the number of partitions is
-usually restricted to 128 in many partitioning tools).
-
-Note that the first sector is still reserved for a
-.B protective MBR
-in the GPT specification. It prevents MBR-only partitioning tools
-from mis-recognizing and overwriting GPT disks.
-
-GPT is always a better choice than MBR, especially on modern hardware with a UEFI
-boot loader.
-.RE
-
-.B DOS-type (MBR)
-.RS
-A DOS-type partition table can describe an unlimited number of partitions. In sector 0
-there is room for the description of 4 partitions (called `primary'). One of
-these may be an extended partition; this is a box holding logical partitions,
-with descriptors found in a linked list of sectors, each preceding the
-corresponding logical partitions. The four primary partitions, present or not,
-get numbers 1-4. Logical partitions are numbered starting from 5.
-
-In a DOS-type partition table the starting offset and the size of each
-partition is stored in two ways: as an absolute number of sectors (given in 32
-bits), and as a
-.B Cylinders/Heads/Sectors
-triple (given in 10+8+6 bits). The former is OK -- with 512-byte sectors this
-will work up to 2 TB. The latter has two problems. First, these C/H/S fields
-can be filled only when the number of heads and the number of sectors per track
-are known. And second, even if we know what these numbers should be, the 24
-bits that are available do not suffice. DOS uses C/H/S only, Windows uses
-both, Linux never uses C/H/S. The
-.B C/H/S addressing is deprecated
-and may be unsupported in some later fdisk version.
-
-.B Please, read the DOS-mode section if you want DOS-compatible partitions.
-.B fdisk
-does not care about cylinder boundaries by default.
-.RE
-
-.B BSD/Sun-type
-.RS
-A BSD/Sun disklabel can describe 8 partitions, the third of which should be a `whole
-disk' partition. Do not start a partition that actually uses its first sector
-(like a swap partition) at cylinder 0, since that will destroy the disklabel.
-Note that a
-.B BSD label
-is usually nested within a DOS partition.
-.RE
-
-.B IRIX/SGI-type
-.RS
-An IRIX/SGI disklabel can describe 16 partitions, the eleventh of which should be an entire
-`volume' partition, while the ninth should be labeled `volume header'. The
-volume header will also cover the partition table, i.e., it starts at block
-zero and extends by default over five cylinders. The remaining space in the
-volume header may be used by header directory entries. No partitions may
-overlap with the volume header. Also do not change its type or make some
-filesystem on it, since you will lose the partition table. Use this type of
-label only when working with Linux on IRIX/SGI machines or IRIX/SGI disks under
-Linux.
-.RE
-
-A sync() and an ioctl(BLKRRPART) (rereading the partition table from disk)
-are performed before exiting when the partition table has been updated.
-
-.SH "DOS mode and DOS 6.x WARNING"
-.B Note that all this is deprecated. You don't have to care about things like
-.B geometry and cylinders on modern operating systems. If you really want
-.B DOS-compatible partitioning then you have to enable DOS mode and cylinder
-.B units by using the '\-c=dos \-u=cylinders' fdisk command-line options.
-
-The DOS 6.x FORMAT command looks for some information in the first sector of
-the data area of the partition, and treats this information as more reliable
-than the information in the partition table. DOS FORMAT expects DOS FDISK to
-clear the first 512 bytes of the data area of a partition whenever a size
-change occurs. DOS FORMAT will look at this extra information even if the /U
-flag is given -- we consider this a bug in DOS FORMAT and DOS FDISK.
-
-The bottom line is that if you use \fBfdisk\fR or \fBcfdisk\fR to change the
-size of a DOS partition table entry, then you must also use
-.BR dd "(1) to " "zero the first 512 bytes"
-of that partition before using DOS FORMAT to format the partition. For
-example, if you were using \fBfdisk\fR to make a DOS partition table entry for
-/dev/sda1, then (after exiting \fBfdisk\fR and rebooting Linux so that the
-partition table information is valid) you would use the command "dd
-if=/dev/zero of=/dev/sda1 bs=512 count=1" to zero the first 512 bytes of the
-partition.
-
-.B fdisk
-usually obtains the disk geometry automatically. This is not necessarily the
-physical disk geometry (indeed, modern disks do not really have anything like a
-physical geometry, certainly not something that can be described in the simplistic
-Cylinders/Heads/Sectors form), but it is the disk geometry that MS-DOS uses for
-the partition table.
-
-Usually all goes well by default, and there are no problems if Linux is the
-only system on the disk. However, if the disk has to be shared with other
-operating systems, it is often a good idea to let an fdisk from another
-operating system make at least one partition. When Linux boots it looks at the
-partition table, and tries to deduce what (fake) geometry is required for good
-cooperation with other systems.
-
-Whenever a partition table is printed out in DOS mode, a consistency check is
-performed on the partition table entries. This check verifies that the
-physical and logical start and end points are identical, and that each
-partition starts and ends on a cylinder boundary (except for the first
-partition).
-
-Some versions of MS-DOS create a first partition which does not begin
-on a cylinder boundary, but on sector 2 of the first cylinder.
-Partitions beginning in cylinder 1 cannot begin on a cylinder boundary, but
-this is unlikely to cause difficulty unless you have OS/2 on your machine.
-
-For best results, you should always use an OS-specific partition table
-program. For example, you should make DOS partitions with the DOS FDISK
-program and Linux partitions with the Linux fdisk or Linux cfdisk programs.
-.SH COLORS
-Implicit coloring can be disabled by an empty file \fI/etc/terminal-colors.d/fdisk.disable\fR.
-
-See
-.BR terminal-colors.d (5)
-for more details about colorization configuration. The logical color names
-supported by
-.B fdisk
-are:
-.TP
-.B header
-The header of the output tables.
-.TP
-.B help-title
-The help section titles.
-.TP
-.B warn
-The warning messages.
-.TP
-.B welcome
-The welcome message.
-
-.SH AUTHORS
-.MT kzak@redhat.com
-Karel Zak
-.ME
-.br
-.MT dave@gnu.org
-Davidlohr Bueso
-.ME
-.br
-.PP
-The original version was written by
-Andries E. Brouwer, A. V. Le Blanc and others.
-
-.SH ENVIRONMENT
-.IP FDISK_DEBUG=all
-enables fdisk debug output.
-.IP LIBFDISK_DEBUG=all
-enables libfdisk debug output.
-.IP LIBBLKID_DEBUG=all
-enables libblkid debug output.
-.IP LIBSMARTCOLS_DEBUG=all
-enables libsmartcols debug output.
-.IP LIBSMARTCOLS_DEBUG_PADDING=on
-use visible padding characters. Requires enabled LIBSMARTCOLS_DEBUG.
-
-.SH "SEE ALSO"
-.BR cfdisk (8),
-.BR mkfs (8),
-.BR partx (8),
-.BR sfdisk (8)
-
-.SH AVAILABILITY
-The fdisk command is part of the util-linux package and is available from
-https://www.kernel.org/pub/linux/utils/util-linux/.
projects / thirdparty / util-linux.git / blobdiff