fdisk - Linux

Overview

The fdisk command in Linux is a versatile disk partitioning tool primarily used to create, delete, resize, and manage disk partitions on a hard drive. It works with various filesystem types and is most effective in storage management, system setup, and recovery actions.

Syntax

The standard syntax for using fdisk is as follows:

fdisk [options] <disk>
  • <disk> refers to the specific block device (e.g., /dev/sda).

Key Syntax Variants:

  • To list all partitions: fdisk -l
  • To interactively edit a disk: fdisk /dev/sda

Options/Flags

Here is a breakdown of some common options used with fdisk:

  • -l: List the partition tables for the specified devices and then exit. If no device is specified, partitions for all devices are shown.
  • t: Change partition type to match specific filesystems or use cases.
  • d: Delete a partition. This option does not delete data persistently but removes the entry from the partition table.
  • n: Add a new partition. The user can specify the type, start, and end sectors.
  • w: Write the changes made to the disk and exit. It’s essential to execute this command to save any changes.
  • q: Quit without saving changes.

Examples

Basic Partition Listing

fdisk -l /dev/sda

This command lists all partitions on the /dev/sda device.

Creating a New Partition

sudo fdisk /dev/sda

After entering the interactive mode:

  1. Press n to create a new partition.
  2. Choose primary (p) or extended (e).
  3. Select the partition number.
  4. Set the start and end sectors.
  5. Press w to write the changes.

Deleting a Partition

sudo fdisk /dev/sda
  1. Enter d.
  2. Choose the partition number to delete.
  3. Press w to save changes and exit.

Common Issues

Problem: Failing to save changes – Users often reboot and find no changes took effect.
Solution: Ensure to press w after making changes in the fdisk utility to write changes to disk.

Problem: Incorrectly identifying disk devices.
Solution: Always double-check the device name with fdisk -l before applying changes to avoid data loss.

Integration

fdisk can be combined with filesystem tools to prepare and format new partitions. For example, after creating a partition with fdisk, you can format it with mkfs.ext4:

sudo mkfs.ext4 /dev/sda1
  • parted, gparted: Alternative partitioning tools offering more features and flexibility.
  • mkfs: Used for creating file systems on partitions made with fdisk.
  • lsblk: Lists all block devices, a useful check before and after using fdisk.

For further reading and advanced options, consult the official Linux man page for fdisk or the documentation of your Linux distribution.