LinuxDevCenter.com
oreilly.comSafari Books Online.Conferences.





Linux in a Nutshell

This directory of Linux commands is from Linux in a Nutshell, 5th Edition.

Click on any of the 687 commands below to get a description and list of available options. All links in the command summaries point to the online version of the book on Safari Bookshelf.

Buy it now, or read it online on Safari Bookshelf.



fdisk

fdisk [options] [device]

System administration command. fdisk displays information about disk partitions, creates and deletes disk partitions, and changes the active partition. It is possible to assign a different operating system to each of the four possible primary partitions, though only one partition is active at any given time. You can also divide a physical partition into several logical partitions. The minimum recommended size for a Linux system partition is 40 MB. Normally, each device will be /dev/hda, /dev/hdb, /dev/sda, /dev/sdb, /dev/hdc, /dev/hdd, and so on. An interactive, menu-driven mode is also available. Note that this command can be destructive if used improperly.

Options

-b sectorsize

Set the size of individual disk sectors. May be 512, 1024, or 2048. Most systems now recognize sector sizes, so this is not necessary.

-l

List partition tables and exit.

-u

Report partition sizes in sectors instead of cylinders.

-s partition

Display the size of partition, unless it is a DOS partition.

-v

Print version number, then exit.

-C cylinders

Specify the number of cylinders on the disk.

-H heads

Specify the number of heads per cylinder.

-S sectors

Specify sectors per track for partitioning.

Commands

a

Toggle a bootable flag on current partition.

b

Edit disklabel of a BSD partition.

c

Toggle DOS compatibility flag.

d

Delete current partition.

l

List all partition types.

m

Main menu.

n

Create a new partition; prompt for more information.

o

Create an empty DOS partition table.

p

Print a list of all partitions and information about each.

q

Quit; do not save.

t

Replace the type of the current partition.

u

Modify the display/entry units, which must be cylinders or sectors.

v

Verify: check for errors, and display a summary of the number of unallocated sectors.

w

Save changes and exit.

x

Switch to expert commands.

Example

To list all partitions currently on the system:

fdisk -l