How to Check the Kernel Version in Ubuntu: Complete Guide for Beginners and Advanced Users

1. Introduction

Ubuntu is one of the most widely used open-source operating systems among Linux distributions. One of the key elements that significantly affects system stability, security, and performance is the “kernel.” The kernel is the core of the OS, acting as a central component that communicates directly between hardware and software, thereby influencing how the entire system operates. For this reason, checking the kernel version is essential for Ubuntu users.

In particular, kernel version checks are often helpful when troubleshooting system issues, improving security, or optimizing performance. Additionally, since security updates are regularly provided for the kernel, it is recommended to keep track of whether the latest updates have been applied.

This guide introduces several practical methods for checking the kernel version in Ubuntu. From using the terminal to confirming it via the graphical user interface (GUI), we cover a wide range of techniques and explain fundamental knowledge and key points related to kernel versions.

2. What Is the Kernel?

In Ubuntu and other Linux distributions, the “kernel” functions as the core of the system. The kernel is the heart of the OS and is responsible for exchanging information between hardware and software. This section explains the roles played by the kernel and highlights its importance.

The Role of the Kernel

The kernel serves as a bridge between hardware and software and performs several crucial functions:

• Resource Management
  The kernel manages system resources such as the CPU, memory, and disk, ensuring applications can use them efficiently. This enables smooth operation even when multiple processes run simultaneously.
• Device Management
  The kernel controls hardware devices such as printers, keyboards, mice, and network cards, allowing applications to use them. It communicates with hardware through device drivers and manages user input and system output.
• Security and Protection
  The kernel ensures system security by separating the user space and kernel space. This prevents regular applications from accessing hardware directly, protecting system stability and security.

The Importance of the Kernel in Ubuntu

Kernel updates in Ubuntu not only enhance system stability but also improve security. When vulnerabilities are discovered, Ubuntu’s development team provides timely updates, making it important to check the kernel version regularly and update it as needed.

As a core component affecting the entire system, the kernel is critically important. The next section explains how to check the kernel version in Ubuntu.

3. How to Check the Kernel Version

There are several ways to check the kernel version in Ubuntu. Here, we introduce simple terminal-based methods and explain how to use each command and interpret the results.

Check the Kernel Version with the uname Command

The most common and simple method is to use the uname command. This command retrieves system information, including the kernel version.

1. Open the terminal.
2. Enter the following command and press Enter.

   uname -r

• The -r option displays the kernel release version. Example output:

   5.4.0-66-generic

In the example above, 5.4.0-66-generic is the kernel version. This version number includes the major version, minor version, and revision details.

Check Using the /proc/version File

You can also confirm the kernel version by viewing the /proc/version file, which contains kernel version and compilation details.

1. Run the following command in the terminal:

   cat /proc/version

Example output:

   Linux version 5.4.0-66-generic (buildd@lcy01-amd64-025) (gcc version 9.3.0 (Ubuntu 9.3.0-17ubuntu1~20.04)) #74-Ubuntu SMP Thu Jan 14 18:28:23 UTC 2021

This output includes not only the kernel version but also compiler version and build date.

Check Using the hostnamectl Command

In Ubuntu 16.04 and later, you can use the hostnamectl command to view system information, including the kernel version.

1. Run the following command in the terminal:

   hostnamectl

Example output:

   Static hostname: ubuntu
         Icon name: computer-vm
           Chassis: vm
        Machine ID: abcdef1234567890
           Boot ID: 123456abcdef98765
    Operating System: Ubuntu 20.04.1 LTS
              Kernel: Linux 5.4.0-66-generic
        Architecture: x86-64

The value displayed after “Kernel:” shows the current kernel version.

Differences Between Each Method and When to Use Them

• uname -r: Best when you simply want to view the kernel version.
• /proc/version: Useful when detailed compilation information is needed.
• hostnamectl: Recommended when reviewing kernel information along with system details.

These are terminal-based methods for checking the kernel version. The next section explains how to confirm it using the GUI.

4. Checking the Kernel Version Using the GUI

In Ubuntu, you can also check the kernel version through the graphical user interface (GUI) without using the command line. The GUI provides an intuitive way for beginners to retrieve system information quickly.

Checking via System Settings

Ubuntu includes a “Settings” menu where you can easily view system details, including the kernel version. Follow these steps:

1. Open the Settings Menu

• Click the system menu (gear icon) on the top-right of the desktop and select “Settings.”

1. Open the “About” or “Details” Section

• Select “About” or “Details” (depending on the version) from the settings menu.

1. Review System Information

• The “About” section displays basic system information, including the kernel version shown under “Kernel” or “Linux Version.” Example:

   Linux 5.4.0-66-generic

Checking with GNOME System Monitor

On the GNOME desktop, you can also check the kernel version using the “GNOME System Monitor” application.

1. Open System Monitor

• Search for “System Monitor” in the app menu and launch it.

1. Select the “System” Tab

• Click the “System” tab to display system and process information.

1. Check the Kernel Version

• Look for the “OS” or “Kernel” field to confirm the version.

Benefits of Checking via the GUI

The GUI approach is ideal for users who prefer visual interaction or are unfamiliar with terminal commands. It offers intuitive access to kernel details without requiring command input.

This concludes the GUI-based methods. Next, we will cover “5. Understanding Kernel Version Components.”

5. Understanding Kernel Version Components

Ubuntu kernel version numbers contain several elements, including major version, minor version, and revision indicators. This section explains each component so you can fully understand what the numbers represent.

Kernel Version Structure

Kernel versions are typically formatted as follows:

5.4.0-66-generic

Using this example, each segment has the following meaning:

1. Major Version (5)

• Indicates large-scale updates or major feature introductions. Increases signify significant improvements or new technologies.

1. Minor Version (4)

• Represents smaller enhancements or improvements on the major version.

1. Revision Number (0)

• Displays bug fixes or security patches applied without major feature changes.

1. Build Number (66)

• Describes Ubuntu-specific versioning and distribution details.

1. Suffix (generic)

• Indicates kernel build configuration or usage type. generic is for general desktop use, while others, such as lowlatency, exist for special use cases.

Benefits of Understanding Kernel Versions

Knowing how kernel versions work helps you determine system stability, security updates, and required compatibility for specific applications.

The next section presents a compatibility table showing Ubuntu releases and their corresponding kernel versions.

6. Kernel Version and Ubuntu Release Compatibility Chart

Each Ubuntu release includes a recommended kernel version, selected for optimal stability, support, and security.

Ubuntu Releases and Kernel Versions

Here is a list of main Ubuntu releases and associated kernel versions:

LTS Versions and Kernel Support

LTS releases (e.g., 20.04, 22.04) feature extended support and emphasize stability. They are widely used in business and server environments.

Kernel Updates per Release

Non-LTS releases deliver cutting-edge kernels with newer features but shorter support cycles. They suit users who prioritize the latest improvements over long-term stability.

Usage of the Compatibility Chart

This chart helps verify system update suitability, software compatibility, and kernel support requirements.

7. How to Update the Kernel

Kernel updates enhance performance and security in Ubuntu. This section explains how to perform kernel updates and key precautions.

Why Update the Kernel?

• Security Enhancements
  Newer kernels fix discovered vulnerabilities and protect the system.
• New Features
  Updated kernels provide new hardware and device support.
• Bug Fixes and Performance Improvements
  Enhancements optimize system behavior and stability.

Kernel Update Procedure

Ubuntu typically updates kernels through standard system updates:

1. Update Package Lists

sudo apt update
sudo apt upgrade

2. Install a Specific Kernel Version

sudo apt install linux-image-<version>-generic

Example:

sudo apt install linux-image-5.15.0-66-generic

3. Reboot to Apply the Kernel

sudo reboot

Kernel Update Precautions

• Check Compatibility
  Older drivers may not work with updated kernels.
• Back Up Data
  Always perform backups before updating crucial system components.
• Keep Old Kernels
  If issues arise, select an older kernel from the GRUB menu during boot.

8. Summary

This article explained how to check your kernel version in Ubuntu, understand version structures, compare kernel-release compatibility, and safely perform updates.

• Kernel Importance
  The kernel manages system resources, hardware communication, and security. Regular checks and updates are recommended.
• Kernel Version Check Methods
  Use uname -r, /proc/version, hostnamectl, or GUI options.
• Understanding Kernel Versions
  Version numbers reveal security and functionality characteristics.
• Safe Kernel Updates
  Follow recommended procedures, check compatibility, back up data, and reboot after installation.

Proper kernel management ensures optimal stability, performance, and security in Ubuntu. Regular monitoring and timely updates will help you maintain a reliable system environment. We hope this guide enhances your understanding and supports your safe and efficient use of Ubuntu.