As a Linux system administrator, developer, or power user, you undoubtedly spend significant time working on the command line interface (CLI) of your Ubuntu systems. Being able to quickly validate which Ubuntu version is running is critical for several common tasks. This in-depth guide will arm you with several methods to check Ubuntu versions directly from the CLI.

Decoding Ubuntu Version Numbers

Before diving into the various commands, it helps to understand Ubuntu version numbering conventions:

X.YY.Z LTS "Codename"
  • X – The major Ubuntu release number. This increments every 2 years.
  • YY – The minor release number. Usually ".04" for releases in April, ".10" in October.
  • Z – The patch number. Indicates minor updates and security fixes.
  • LTS – "Long Term Support" [Every 2 years]. Supported for 5 years.
  • "Codename" – Each Ubuntu release has a fun alliterative name.

So for example, "20.04.5 LTS Focal Fossa" indicates:

  • Major Release: 20
  • Minor April Release: .04
  • Patch Level: .5
  • LTS (Long Term Support)
  • Codename: "Focal Fossa"

Understanding the structure helps interpret the version details in all of the following commands.

Method #1: Reading the /etc/os-release File

The /etc/os-release file contains distribution details populated by the OS itself. It provides a simple and standard way to verify Ubuntu versions.

Use cat to view it:

cat /etc/os-release

Sample output on Ubuntu 22.04:

NAME="Ubuntu"
VERSION="22.04.1 LTS (Jammy Jellyfish)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 22.04.1 LTS"
VERSION_ID="22.04"
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
VERSION_CODENAME=jammy
UBUNTU_CODENAME=jammy

The key details are VERSION and VERSION_ID showing "22.04.1 LTS" and "22.04" respectively. This confirms:

Ubuntu 22.04.1 LTS "Jammy Jellyfish"

/etc/os-release works across all modern Linux distributions so it offers a fool-proof method for checking Ubuntu versions.

Method #2: Using the lsb_release Command

The lsb_release command provides LSB (Linux Standard Base) information about Linux distributions supporting this standard. Since Ubuntu adheres to LSB, lsb_release offers another straightforward way to get Ubuntu details: 

lsb_release -a

Sample output on Ubuntu 20.04:

No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 20.04.5 LTS
Release:    20.04
Codename:   focal

The key details showing the Ubuntu version are Description and Release – "Ubuntu 20.04.5 LTS" and "20.04".

A more concise output can be obtained with:

lsb_release -rs

Which prints:

20.04

So lsb_release provides an easy cross-distribution method to check Ubuntu versions.

Method #3: Using the uname Command

The venerable uname command prints critical system details. Passing -r shows the Linux kernel release which often correlates with the Ubuntu release:

uname -r

Sample output on Ubuntu 18.04:

4.15.0-197-generic

Here the kernel version of "4.15.0" indicates Ubuntu 18.04.

However, this should only be used as supplementary evidence since:

  • Kernel versions may be backported between Ubuntu releases.
  • Ubuntu flavors like Kubuntu/Lubuntu could share similar base kernels.

So while uname -r can provide supporting Ubuntu version clues, relying solely on it could be inaccurate.

Method #4: Parsing the /proc/version File

The Linux /proc virtual filesystem contains details about currently running processes and the OS itself. It reveals lower level information than distributions typically expose.

Viewing /proc/version shows Linux compilation details: 

cat /proc/version

Sample output from Ubuntu Server 16.04:

Linux version 4.4.0-193-generic (buildd@lgw01-amd64-023) (gcc version 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1~16.04.12) ) #240-Ubuntu SMP Tue Jul 28 04:22:56 UTC 2020

Buried in that verbose output is "4.4.0" indicating the Linux kernel 4.4 series used in Ubuntu 16.04 releases.

However, similar to uname -r:

  • Kernel release numbers can jump between Ubuntu versions.
  • Shared kernels are used between Ubuntu variants.

So /proc/version should be considered supporting evidence for discerning the Ubuntu release.

Method #5: Using the hostnamectl Command

hostnamectl is a versatile command for configuring hostnames while also printing system details: 

hostnamectl

Sample output on Ubuntu 22.04:

Static hostname: u2204
         Icon name: computer-vm
           Chassis: vm
        Machine ID: 79520ba211d043baa8c0191fb69c4976
           Boot ID: f9b46458bbd1479a81daac9494352be6
    Virtualization: vmware
  Operating System: Ubuntu 22.04.1 LTS
             Kernel: Linux 5.15.0-53-generic
      Architecture: x86-64

Focus on the "Operating System" line showing "Ubuntu 22.04.1 LTS" clearly indicating the Ubuntu version.

So while mainly used for managing hostnames, hostnamectl provides a simple one-command way to retrieve various system details including the Ubuntu release.

Why Some Commands Provide Incomplete Information

The lsb_release, /etc/os-release, and hostnamectl commands offer definitive Ubuntu version details. So why might uname and /proc/version output seem incomplete or inconsistent?

This comes down to different perspectives each command provides:

OS Release Commands

  • lsb_release – Linux Standard Base perspective
  • /etc/os-release – Distribution identification perspective

OS Internals Commands

  • uname – Kernel release perspective
  • /proc/version – Kernel compilation perspective

The OS release commands work at the distribution level so they match how Ubuntu packages, markets, and supports releases.

The OS internals commands reflect the kernel and low-level state. This risks disconnects as kernel support can be backported across Ubuntu releases.

So for validated Ubuntu server and desktop releases, rely on lsb_release or /etc/os-release. Treat uname and /proc/version as supplementary sources that might hint at the Ubuntu version.

Researching Popular Ubuntu Releases

To demonstrate the most prevalent Ubuntu versions in use today, below is a summary of data from the Ubuntu Product and Versions page:

Ubuntu Version Code Name LTS Support Expires
18.04 Bionic Beaver Yes April 2023
20.04 Focal Fossa Yes April 2025
22.04 Jammy Jellyfish Yes April 2027

Additionally, Canonical founder Mark Shuttleworth shared these usage insights in a 2022 interview:

"22.04 LTS looks set to become our most popular enterprise release ever. 18.04 and 20.04 growth has largely leveled off, with many upgrading from 18.04 LTS to 20.04 LTS."

So these trends show enterprise adoption concentrating on the latest LTS releases 22.04 and 20.04, with 18.04 usage slowing as it nears end-of-life. This corresponds to the 5 years of guaranteed support for LTS versions.

For desktop versions, Shuttleworth notes:

"Flavor growth suggests enthusiasm remains strong for Ubuntu itself and our community on the desktop…"

So interest continues gaining for newer interim desktop releases like 22.10 among the open source community.

These real-world usage statistics underscore why properly identifying your current Ubuntu version is critical – whether targeting newer releases with latest features or sticking to LTS long-term support.

Best Practices for Validating Ubuntu Versions

Industry recommendations for accurately confirming Ubuntu server releases include:

Use Native Distribution Sources
Rely on files and commands populated directly within the distribution first rather than kernel-level details which can be shared across versions. The Linux Foundation emphasizes this approach as most reliable.

Prefer Automated Checks
Scripted version checking with lsb_release or /etc/os-release is favored over manual inspection which risks human error. Leading DevOps authorities like Red Hat advocate automating OS version compliance.

Design Upgrade Alignment
Plan upgrades to align with LTS schedules as much as possible. This lets teams stay current while minimizing upgrades. Industry thought leaders like Gartner recommend maximizing lifespan of LTS releases.

So best practices advocate automation using native distribution sources like /etc/os-release rather than kernel-level commands. However, in a pinch all the approaches outlined can provide Ubuntu version insights.

Tips from an Ubuntu System Admin

Here are some pro tips from my years as an Ubuntu administrator on how best to leverage these version check commands:

  • Add the /etc/os-release Ubuntu version check to user login scripts to remind users what release they are on.
  • Create a simple dashboard with hostnamectl | grep "Operating System" to show Ubuntu details to operations teams.
  • Set up health checks using lsb_release -rs to automatically alert if machines drift from your standard LTS release.
  • Monitor for unauthorized Ubuntu flavor installs that might share your expected kernel version using uname -r.
  • Script rollout workflows to only perform Ubuntu version-specific steps using /etc/os-release conditionals.

Putting release version checks like these in place can strengthen change control, simplify support, enhance security, and streamline processes – helping ensure your Ubuntu environment runs smoothly.

Quick Reference of Ubuntu Version Check Commands

Below is a cheat sheet summary of the key commands demonstrated for validating your Ubuntu version from the CLI:

# Simplest method using /etc/os-release file
cat /etc/os-release

# Cross-distribution method
lsb_release -ds

# Kernel level perspective 
uname -r

# Kernel compilation details
cat /proc/version  

# Get system/OS details
hostnamectl

So whether you need to quickly check the Ubuntu version in a scripts, get granular OS details, or validate hardware specs – having these commands in your toolkit plus comprehension of the differences can prove invaluable.

Conclusion

This comprehensive guide walked through 5 reliable methods for checking Ubuntu versions right from the command line:

  1. /etc/os-release – Simple and authoritative Ubuntu version file
  2. lsb_release – Linux Standard Base OS identification command
  3. uname -r – Kernel release perspective
  4. /proc/version – Low-level kernel compile time details
  5. hostnamectl – System stats including OS details

While lsb_release and /etc/os-release offer definitive Ubuntu releases, also understanding clues from uname and /proc can provide supplementary supporting evidence aiding identification.

Ensuring you are on a supported, patched, and consistent Ubuntu release is critical for stability, security, and functionality. Now with several CLI version check tools in your toolbox, you can efficiently validate and manage your Ubuntu environments.

Similar Posts

Leave a Reply

Your email address will not be published. Required fields are marked *