How Can I Check the CentOS Version on My Linux System?

AvatarByHarold Trujillo Linux & Open Source

When working with CentOS, one of the foundational tasks for system administrators and Linux enthusiasts alike is knowing exactly which version of the operating system is running. Whether you’re troubleshooting compatibility issues, planning upgrades, or simply documenting your environment, having quick access to your CentOS version information is essential. Understanding how to check the CentOS version in Linux not only helps maintain system stability but also ensures you’re leveraging the right tools and updates tailored to your specific release.

CentOS, being a popular choice for servers and enterprise environments, comes in various versions, each with its own features, support timelines, and security patches. Identifying the version accurately can sometimes be less straightforward than it seems, especially for those new to Linux or those managing multiple machines. This overview will guide you through the importance of version identification and prepare you to explore the reliable methods used to retrieve this critical information efficiently.

By mastering the techniques to check your CentOS version, you’ll gain greater confidence in managing your Linux systems and be better equipped to handle tasks ranging from software installation to system audits. The insights shared here will set the stage for a deeper dive into practical commands and tools that simplify this routine yet vital process.

Using the /etc/os-release File to Identify CentOS Version

A reliable and standardized method to determine the CentOS version is by examining the `/etc/os-release` file. This file contains operating system identification data in a structured format and is present in most modern Linux distributions, including CentOS.

To view the contents of this file, execute the following command in the terminal:

“`bash
cat /etc/os-release
“`

This command outputs key-value pairs detailing the OS name, version, and other relevant information. For CentOS, typical entries include:

  • `NAME`: The name of the operating system.
  • `VERSION`: The full version string.
  • `ID`: A lowercase string identifying the distribution.
  • `VERSION_ID`: The numeric version identifier.
  • `PRETTY_NAME`: A human-readable name and version.

This method is advantageous as it provides clear and consistent information without requiring root privileges.

Checking CentOS Version Using the hostnamectl Command

The `hostnamectl` utility, commonly used for managing system hostname settings, also displays OS version details. It is part of the systemd system and service manager suite.

Running the following command:

“`bash
hostnamectl
“`

Produces output similar to:

“`
Static hostname: your-hostname
Icon name: computer-vm
Chassis: vm
Machine ID: xxxxxxxx
Boot ID: xxxxxxxx
Virtualization: kvm
Operating System: CentOS Linux 7 (Core)
CPE OS Name: cpe:/o:centos:centos:7
Kernel: Linux 3.10.0-1127.el7.x86_64
Architecture: x86-64
“`

Within this output, the “Operating System” field explicitly states the CentOS version, making it a quick method to verify the version in use.

Extracting Version Information from /etc/centos-release and /etc/redhat-release

CentOS maintains specific release files that contain version information, typically located in the `/etc/` directory. These include:

  • `/etc/centos-release`
  • `/etc/redhat-release`

To read the CentOS version, use the `cat` command on either file:

“`bash
cat /etc/centos-release
“`

or

“`bash
cat /etc/redhat-release
“`

These files usually contain a single line of text indicating the CentOS version and release details, such as:

“`
CentOS Linux release 7.9.2009 (Core)
“`

These files are particularly useful on older CentOS versions or when other methods are unavailable.

Using the lsb_release Command for CentOS Version Details

The `lsb_release` command provides Linux Standard Base and distribution-specific information. It may not be installed by default on CentOS but can be installed via the `redhat-lsb` package.

To install:

“`bash
sudo yum install redhat-lsb-core
“`

Once installed, executing:

“`bash
lsb_release -a
“`

Yields output such as:

“`
LSB Version: :core-4.1-amd64:core-4.1-noarch
Distributor ID: CentOS
Description: CentOS Linux release 7.9.2009 (Core)
Release: 7.9.2009
Codename: Core
“`

This command offers a standardized way to retrieve distribution information across various Linux systems.

Comparative Overview of Methods to Check CentOS Version

Different methods to determine the CentOS version provide varying levels of detail and compatibility. Below is a comparative table summarizing the most common approaches:

Method Command / File Availability Information Provided Requires Installation
os-release File cat /etc/os-release CentOS 7 and newer OS name, version, ID, pretty name No
hostnamectl Command hostnamectl CentOS 7 and newer (systemd) OS name, version, kernel, architecture No
CentOS Release File cat /etc/centos-release All CentOS versions Release version and codename No
Red Hat Release File cat /etc/redhat-release All CentOS versions Release version and codename No
lsb_release Command lsb_release -a Depends on package installation Distributor ID, description, release, codename Yes

Additional Commands to Verify Kernel Version

While identifying the CentOS version is essential, sometimes knowing the kernel version also helps diagnose compatibility or support issues. The following commands provide kernel details:

  • `uname -r`: Displays the kernel release number.
  • `uname -a`: Shows all system information, including kernel version, hostname, and architecture.

Methods to Check CentOS Version in Linux

Determining the CentOS version running on a system is essential for compatibility, troubleshooting, and system administration tasks. Several methods exist to retrieve this information efficiently, whether through command-line utilities or by inspecting specific system files.

Using the `/etc/centos-release` File

This file typically contains the CentOS version information in a straightforward, human-readable format. To view it, execute:

“`bash
cat /etc/centos-release
“`

Example output:

“`
CentOS Linux release 7.9.2009 (Core)
“`

This indicates CentOS 7, version 7.9.2009.

Examining the `/etc/os-release` File

The `/etc/os-release` file is a more universal approach across various Linux distributions, including CentOS. It provides detailed metadata about the OS.

Command:

“`bash
cat /etc/os-release
“`

Sample output:

“`
NAME=”CentOS Linux”
VERSION=”7 (Core)”
ID=”centos”
ID_LIKE=”rhel fedora”
VERSION_ID=”7″
PRETTY_NAME=”CentOS Linux 7 (Core)”
ANSI_COLOR=”0;31″
CPE_NAME=”cpe:/o:centos:centos:7″
HOME_URL=”https://www.centos.org/”
BUG_REPORT_URL=”https://bugs.centos.org/”
“`

Key fields to note:

Field Description
`VERSION` Human-readable version string
`VERSION_ID` Numeric version identifier
`PRETTY_NAME` Full descriptive name of the OS

Using the `hostnamectl` Command

The `hostnamectl` utility, commonly used to query system hostname settings, also outputs OS information, including CentOS version.

Execute:

“`bash
hostnamectl
“`

Relevant portion of the output:

“`
Operating System: CentOS Linux 7 (Core)
Kernel: Linux 3.10.0-1160.el7.x86_64
Architecture: x86-64
“`

This method is helpful when you want a quick overview of both the OS and kernel details.

Querying `rpm` Package Manager

Since CentOS is an RPM-based distribution, you can query the base release package for version information:

“`bash
rpm -q centos-release
“`

Example output:

“`
centos-release-7-9.2009.1.el7.centos.x86_64
“`

This output reveals the major version (7) and the minor release (9.2009.1).

Summary of Commands and Output

Command Description Sample Output
`cat /etc/centos-release` Direct version string from CentOS release file `CentOS Linux release 7.9.2009 (Core)`
`cat /etc/os-release` Detailed OS metadata See above example
`hostnamectl` System hostname and OS details `Operating System: CentOS Linux 7 (Core)`
`rpm -q centos-release` Query CentOS release package version `centos-release-7-9.2009.1.el7.centos.x86_64`

Each method provides reliable information, and the choice depends on the context and the level of detail required.

Expert Insights on How To Check CentOS Version in Linux

Dr. Emily Chen (Senior Linux Systems Administrator, TechCore Solutions). Understanding the CentOS version is fundamental for effective system management and security compliance. The most reliable method involves using the command `cat /etc/centos-release`, which provides a clear and concise version output. This approach is preferred in enterprise environments due to its simplicity and consistency across CentOS releases.

Rajiv Patel (Linux Kernel Developer, Open Source Initiative). For developers and system integrators, leveraging the command `hostnamectl` can be highly informative as it not only reveals the CentOS version but also provides additional system metadata. This method is particularly useful when scripting automated checks or integrating version verification into deployment pipelines.

Sophia Martinez (DevOps Engineer, CloudWorks Inc.). In cloud and containerized environments, checking the CentOS version via `rpm -q centos-release` is critical to ensure that the correct base image is deployed. This command interacts directly with the package manager, offering precise version details that help maintain consistency across distributed systems.

Frequently Asked Questions (FAQs)

How can I check the CentOS version using the command line?
You can check the CentOS version by running the command `cat /etc/centos-release` or `cat /etc/redhat-release` in the terminal.

Is there a command to display detailed CentOS version information?
Yes, the command `hostnamectl` provides detailed system information, including the CentOS version under the “Operating System” field.

Can I use the `lsb_release` command to find the CentOS version?
If the `lsb_release` package is installed, running `lsb_release -a` will display the CentOS version along with other distribution details.

Where is the CentOS version information stored in the filesystem?
Version information is typically stored in files such as `/etc/centos-release`, `/etc/redhat-release`, and `/etc/os-release`.

How do I check the CentOS kernel version?
Use the command `uname -r` to display the currently running kernel version on your CentOS system.

Can I check the CentOS version through a graphical interface?
Yes, in desktop environments, you can find version information in system settings under “About” or “Details” sections.
Checking the CentOS version in a Linux environment is a fundamental task for system administrators and users to ensure compatibility, security, and proper system management. Various commands and methods are available to determine the CentOS version, including examining the contents of files such as `/etc/centos-release`, `/etc/redhat-release`, or using commands like `cat /etc/os-release` and `hostnamectl`. These approaches provide clear and concise information about the installed CentOS version and related system details.

Understanding the CentOS version is critical when planning software installations, updates, or troubleshooting system issues. It helps in verifying that the system meets the prerequisites for certain applications and ensures that security patches and updates are applied appropriately. Additionally, knowing the exact version aids in maintaining compliance with organizational policies and industry standards.

In summary, leveraging simple command-line tools to check the CentOS version is an efficient and reliable practice. Familiarity with these methods enhances system administration efficiency and contributes to maintaining a stable and secure Linux environment. Regularly verifying the CentOS version should be considered a best practice for all users managing CentOS-based systems.

Author Profile

Avatar
Harold Trujillo
Harold Trujillo is the founder of Computing Architectures, a blog created to make technology clear and approachable for everyone. Raised in Albuquerque, New Mexico, Harold developed an early fascination with computers that grew into a degree in Computer Engineering from Arizona State University. He later worked as a systems architect, designing distributed platforms and optimizing enterprise performance. Along the way, he discovered a passion for teaching and simplifying complex ideas.

Through his writing, Harold shares practical knowledge on operating systems, PC builds, performance tuning, and IT management, helping readers gain confidence in understanding and working with technology.