cfdisk Command Linux: Complete Guide to Curses-based Partition Management

The cfdisk command is a powerful, user-friendly partition table editor for Linux systems that provides a curses-based interface for managing disk partitions. Unlike the traditional fdisk command, cfdisk offers an intuitive menu-driven approach that makes partition management more accessible for both beginners and experienced users.

What is cfdisk Command?

The cfdisk utility is a curses-based disk partition table manipulator that allows users to create, delete, and modify partitions on storage devices. It’s part of the util-linux package and provides a more visual and interactive alternative to command-line partition tools.

Key Features of cfdisk

• Interactive Interface: Menu-driven operation with arrow key navigation
• Visual Partition Display: Clear representation of partition layout
• Real-time Updates: Immediate visualization of changes
• Multiple Partition Types: Support for various partition types and file systems
• Safety Features: Changes aren’t written until explicitly confirmed

cfdisk Command Syntax

The basic syntax for the cfdisk command is:

cfdisk [options] [device]

Common Options

• -h, --help: Display help information
• -V, --version: Show version information
• -L, --color[=when]: Colorize output (auto, always, never)
• -z, --zero: Start with zeroed partition table

Installing cfdisk

On most Linux distributions, cfdisk is pre-installed as part of the util-linux package. If it’s not available, you can install it:

Ubuntu/Debian

sudo apt update
sudo apt install util-linux

CentOS/RHEL/Fedora

sudo yum install util-linux-ng
# or for newer versions
sudo dnf install util-linux

Basic cfdisk Usage

Launching cfdisk

To start cfdisk on a specific device:

sudo cfdisk /dev/sdb

Important: Always use sudo when running cfdisk as it requires administrative privileges to modify partition tables.

Understanding the cfdisk Interface

When you launch cfdisk, you’ll see a screen divided into several sections:

• Partition List: Shows existing partitions with details
• Menu Options: Available actions at the bottom
• Device Information: Disk size and model information
• Free Space: Unallocated areas on the disk

Creating Partitions with cfdisk

Step-by-Step Partition Creation

1. Launch cfdisk:

   sudo cfdisk /dev/sdb

2. Select Free Space: Use arrow keys to highlight free space
3. Create New Partition: Press ‘N’ or select “New” from the menu
4. Choose Partition Type:
   • Primary (for bootable partitions)
   • Extended (container for logical partitions)
   • Logical (within extended partition)
5. Specify Size: Enter the desired partition size (e.g., 10G, 500M)

Example: Creating a 10GB Primary Partition

# Launch cfdisk
sudo cfdisk /dev/sdb

# Navigate to free space and press 'N'
# Select "primary" when prompted
# Enter size: 10G
# Press Enter to confirm

Modifying Partition Types

Changing Partition Type

To modify a partition’s type:

1. Select the partition using arrow keys
2. Press ‘T’ or select “Type” from the menu
3. Choose from available partition types:
   • Linux filesystem (83)
   • Linux swap (82)
   • Linux LVM (8e)
   • NTFS (7)
   • FAT32 (b)

Common Partition Types

Deleting Partitions

To remove a partition:

1. Select the partition to delete
2. Press ‘D’ or select “Delete” from the menu
3. Confirm the deletion

Warning: Deleting a partition removes all data stored on it. Always backup important data before deletion.

Managing Partition Flags

Setting Bootable Flag

To make a partition bootable:

1. Select the desired partition
2. Press ‘B’ or select “Bootable” from the menu
3. The partition will be marked with an asterisk (*)

Other Available Flags

• Boot: Makes partition bootable
• Required: Marks partition as required by the system
• LBA: Uses Logical Block Addressing

Working with Different Partition Table Types

MBR (Master Boot Record)

MBR is the traditional partition table format with these characteristics:

• Maximum 4 primary partitions
• Disk size limit of 2TB
• One extended partition can contain multiple logical partitions

GPT (GUID Partition Table)

GPT is the modern partition table format offering:

• Support for disks larger than 2TB
• Up to 128 partitions by default
• Better data integrity with redundant headers
• Required for UEFI boot

Converting Between Partition Table Types

To create a GPT partition table:

# Start cfdisk and select "gpt" when prompted
sudo cfdisk /dev/sdb

# Or specify GPT explicitly
sudo cfdisk -t gpt /dev/sdb

Practical Examples

Example 1: Setting up a Basic Linux System

Creating partitions for a typical Linux installation:

1. Boot Partition (500MB):

   sudo cfdisk /dev/sda
   # Create 500M primary partition
   # Set type to Linux (83)
   # Make bootable

2. Root Partition (20GB):

   # Create 20G primary partition
   # Set type to Linux (83)

3. Swap Partition (4GB):

   # Create 4G partition
   # Set type to Linux swap (82)

4. Home Partition (remaining space):

   # Create partition with remaining space
   # Set type to Linux (83)

Example 2: Creating a Data Storage Setup

Setting up a disk for data storage with multiple partitions:

sudo cfdisk /dev/sdb

# Create multiple data partitions:
# 1. Documents: 50GB (Linux type)
# 2. Media: 100GB (Linux type)  
# 3. Backup: Remaining space (Linux type)

Saving Changes

Writing Changes to Disk

After making all desired changes:

1. Press ‘W’ or select “Write” from the menu
2. Type “yes” to confirm writing changes
3. Press ‘Q’ or select “Quit” to exit cfdisk

Important: Changes are not permanent until you write them to disk. You can quit without writing to discard all changes.

Advanced cfdisk Features

Resizing Partitions

While cfdisk doesn’t directly support resizing, you can:

1. Delete the partition
2. Create a new partition in the same location with different size
3. Use resize2fs or similar tools afterward to resize the filesystem

Viewing Partition Information

To view detailed partition information:

• Use arrow keys to select a partition
• Partition details appear in the information area
• Size, type, and flags are displayed

Troubleshooting Common Issues

Permission Denied Errors

If you encounter permission errors:

# Ensure you're using sudo
sudo cfdisk /dev/sdb

# Check device permissions
ls -l /dev/sdb

Device Busy Errors

If the device is busy:

# Check mounted partitions
mount | grep /dev/sdb

# Unmount if necessary
sudo umount /dev/sdb1

# Check for swap usage
swapon --show

Partition Table Corruption

For corrupted partition tables:

# Backup existing partition table
sudo sfdisk -d /dev/sdb > partition_backup.txt

# Create new partition table
sudo cfdisk -z /dev/sdb

Best Practices for Using cfdisk

Safety Guidelines

• Always backup data before modifying partitions
• Double-check device names to avoid accidental data loss
• Use test environments when learning partition management
• Document partition layouts for future reference

Planning Partition Layout

• Determine required partition types and sizes
• Consider future expansion needs
• Plan for system requirements (boot, swap, root)
• Leave some unallocated space for flexibility

Alternatives to cfdisk

Command-line Tools

• fdisk: Traditional command-line partition editor
• parted: GNU partition editor with scripting support
• sfdisk: Script-oriented partition table manipulator

Graphical Tools

• GParted: GNOME partition editor
• KDE Partition Manager: KDE’s partition management tool
• GNOME Disks: Simple disk management utility

Conclusion

The cfdisk command provides an excellent balance between functionality and ease of use for Linux partition management. Its curses-based interface makes it more approachable than traditional command-line tools while still offering powerful partition manipulation capabilities.

Whether you’re setting up a new Linux system, managing storage devices, or reorganizing disk layouts, cfdisk offers the tools needed to accomplish these tasks safely and efficiently. Remember to always backup important data and carefully plan your partition layout before making changes.

By mastering cfdisk, you’ll have a valuable tool in your Linux administration toolkit that can handle most partition management tasks with confidence and precision.