Understanding the cfdisk Command in Linux: A Guide for Advanced Users

Disk partitioning is an essential task in Linux, especially for system administrators or users managing multiple drives. One of the tools available for partition management is the cfdisk command, a simple yet powerful text-based partition editor. While graphical partition editors like GParted provide a user-friendly interface, cfdisk offers greater control through the command line, making it ideal for advanced users who prefer working without a graphical environment.

In this blog post, we’ll explore the cfdisk command in detail, discussing its use cases, advantages, and practical examples to help you master disk partitioning tasks on Linux.

What is cfdisk?

cfdisk stands for ***curses-based fdisk*** . It is a simplified version of the more traditional fdisk command but with a menu-driven interface based on the curses library. This allows users to interactively manage disk partitions in a text-based environment.

cfdisk is particularly useful for those who find fdisk's command-line interface too complex or want a faster way to create, delete, and modify partitions. While it lacks some of the advanced features of parted, it is perfect for common partitioning tasks such as:

- Creating partitions
• Deleting partitions
• Changing partition types (e.g., setting a partition as Linux, swap, or NTFS)
• Setting partitions as bootable

cfdisk operates on block devices such as /dev/sda, /dev/nvme0n1, or /dev/mmcblk0, and changes are only committed when you write them to the disk. Until that point, no data is altered, making it a relatively safe tool to experiment with.

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Installing cfdisk

Before you begin, ensure that cfdisk is installed on your system. Most Linux distributions include cfdisk by default, but if it is missing, you can install it using your package manager.

For ***Debian/Ubuntu*** systems:

sudo apt-get install util-linux

For ***Fedora*** :

sudo dnf install util-linux

For ***Arch Linux*** :

sudo pacman -S util-linux

The cfdisk tool is part of the util-linux package, which is widely available on almost all Linux distributions.

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Basic Usage and Interface

To begin working with cfdisk, you need to specify the disk you want to manage. For example, to work on the first disk (/dev/sda), run the following command:

sudo cfdisk /dev/sda

This command will open an interactive text-based interface where you can perform various partitioning tasks.

Key Sections of the Interface:

- ***Disk Information*** : At the top of the screen, you’ll see information about the disk you’re working on, including the size of the disk and the partition table type (e.g., DOS or GPT).
• Partition Table : Below the disk information is a list of current partitions on the disk. Each partition is displayed with its start and end points, size, file system type, and label.
• Menu Options : At the bottom, you’ll find a menu that provides options such as Create , Delete , Type , Write , and Quit . You can navigate through these options using the arrow keys and select them by pressing Enter .

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Working with Partition Tables

Before creating or modifying partitions, you must ensure that the partition table is correctly set up. cfdisk supports both ***DOS*** and ***GPT*** partition tables.

Creating a New Partition Table

To create a new partition table:

- Open cfdisk on the disk you want to partition: sudo cfdisk /dev/sda
• Use the arrow keys to select the [Label] option, which allows you to create a new partition table.
• Select either gpt or dos depending on your requirements:
- ***GPT*** (GUID Partition Table) is suitable for disks larger than 2 TB or when using UEFI boot.
• DOS is more common for legacy BIOS systems and smaller disks.

Choosing the correct partition table is crucial for compatibility with your system’s boot method.

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Creating Partitions with cfdisk

Once the partition table is set, you can begin creating partitions. Here’s an example where we create three partitions:

- A root partition (/) of 50 GB
• A swap partition of 8 GB
• A home partition (/home) with the remaining space
- ***Create Root Partition*** :
- In the cfdisk interface, select ***[New]*** to create a new partition.
• Choose the size of the partition. For this example, enter 50G for the root partition.
• After setting the size, you’ll be prompted to choose whether the partition should be Primary or Logical . For the first partition on a DOS table, select Primary .
• Now, mark the partition as bootable by selecting [Bootable] . This is required for the partition from which you will boot your system.
• Create Swap Partition :
- After creating the root partition, select ***[New]*** again to create another partition.
• Enter 8G as the size of this partition for the swap area.
• Use the [Type] option to change the partition type to 82 (Linux swap) .
• Create Home Partition :
- Finally, use the remaining space to create the home partition. Select ***[New]*** and assign the remaining size.
• No special settings are required for the home partition unless you want to change the file system type.

Example:

After completing these steps, the partition table might look something like this:

/dev/sda1   50G   Linux filesystem
/dev/sda2   8G    Linux swap
/dev/sda3   Remaining size  Linux filesystem

Once the partitions are set, navigate to ***[Write]*** to commit your changes to disk. cfdisk will ask you to type "yes" to confirm that you want to write the changes. Afterward, you can quit the program by selecting ***[Quit]*** .

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Deleting and Modifying Partitions

Deleting a Partition

If you need to delete a partition, use the ***[Delete]*** option in the cfdisk interface:

- Select the partition you want to delete using the arrow keys.
• Select [Delete] , and the partition will be removed from the partition table.

Deleted partitions remain uncommitted until you choose to write the changes. This gives you the flexibility to undo changes before they are final.

Changing Partition Types

Sometimes you might want to change the type of an existing partition (e.g., setting a partition as ***swap*** or ***EFI system*** ). Use the ***[Type]*** option to assign a different type to the selected partition.

For example:

Type -> 82 (Linux swap)

or

Type -> EF00 (EFI system)

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Practical cfdisk Use Cases

1. Preparing a Disk for Linux Installation

When installing a new Linux distribution, partitioning is often required. Using cfdisk, you can easily create partitions for ***root*** , ***home*** , ***swap*** , and ***boot*** partitions before installation.

sudo cfdisk /dev/sda

Then create the necessary partitions (e.g., /, /boot, /home, swap) and set the appropriate types and bootable flags.

2. Partitioning a New External Drive

Suppose you have a new external drive (/dev/sdb) that you want to partition for use as a backup drive. Using cfdisk, you can create a large partition and set the partition type to ***Linux filesystem*** for ext4 formatting later.

sudo cfdisk /dev/sdb

Create a partition with the desired size and write the changes. Once done, format the partition using the mkfs command:

sudo mkfs.ext4 /dev/sdb1

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Advantages and Limitations of cfdisk

Advantages:

- ***Intuitive Interface*** : The text-based interface is easy to navigate compared to fdisk.
• Safe to Use : Until changes are written to disk, cfdisk does not modify your data.
• Wide Compatibility : Supports both DOS and GPT partition tables.

Limitations:

- ***Limited Features*** : Compared to parted, cfdisk lacks advanced features such as resizing partitions or aligning them to sector boundaries.
• Non-Graphical : While more user-friendly than fdisk, it still requires working in a text-based interface, which might not be ideal for all users.

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Conclusion

The cfdisk command is a straightforward yet powerful tool for managing partitions in Linux. For advanced users, it offers an efficient way to perform common partitioning tasks without the complexity of fdisk or the need for a full graphical interface. Whether you’re setting up a new disk, preparing for an installation, or managing storage on a server, cfdisk provides a reliable method to create, delete, and modify partitions with ease.

By mastering cfdisk, you gain the ability to handle disk management tasks in almost any environment, from desktop setups to headless servers.