Find Linux / UNIX Kernel Version Command

How do I find out what kernel version I am currently running under Debian Linux or any other Linux distribution using a shell prompt? How do I find out Unix kernel version? How can I find out my Linux / UNIX kernel version using the ssh command?

You need to use the uname command to print certain system information such as:

  1. Linux Kernel version and name.
  2. Print the Unix machine hardware name.
  3. Find out about server processor type.
  4. Display the operating system and more.

uname command to display the Linux or Unix kernel version

This command works under all Linux distributions and other UNIX-like operating systems such as FreeBSD, OpenBSD, Solaris, HP UX, OS X and friends. Type the following command to see running kernel version:
$ uname -r
Output taken from Linux based system:

2.6.22-14-generic

Where,

  • 2 : Kernel version
  • 6 : The major revision of the kernel
  • 22 : The minor revision of the kernel
  • 14 : Immediate fixing / bug fixing for critical error
  • generic : Distribution specific sting. For example, Redhat appends string such as EL5 to indicate RHEL 5 kernel.

Another common usage is as follows:
$ uname -mrsn
Output taken from Linux:

Linux moon.nixcraft.in 2.6.18-53.1.4.el5 x86_64

Here is another output from RHEL 8:

My RHEL 8 kernel version

Outputs from my OS X Unix desktop

$ uname -a  
Darwin desktop01 13.0.0 Darwin Kernel Version 13.0.0: Thu Sep 19 22:22:27 PDT 2013; root:xnu-2422.1.72~6/RELEASE_X86_64 x86_64

Outputs from OpenBSD Unix server

$ uname -mrs
OpenBSD 5.4 amd64

How to find the kernel version with /proc/version file (Linux only command)

You can also obtain kernel version from /proc/version file by using cat command as follows:
$ less /proc/version
$ more /proc/version
$ cat /proc/version

Sample outputs:

Linux version 2.6.18-53.1.4.el5 ([email protected]) (gcc version 4.1.2 20070626 (Red Hat 4.1.2-14)) #1 SMP Wed Nov 14 10:37:27 EST 2007

Related media

See how to use uname and other commands to find the kernel version on Linux or Unix-like oses:

Package management tools (Linux only command)

You can list all installed kernel and its version with the following command under RHEL / CentOS / Suse / Fedora Linux :
$ rpm -q kernel
Output:

kernel-2.6.18-53.el5
kernel-2.6.18-53.1.4.el5

If you are using Debian / Ubuntu, try:
$ dpkg --list | grep linux-image
Output:

ii  linux-image                            2.6.22.14.21                         Generic Linux kernel image.
rc  linux-image-2.6.20-15-generic          2.6.20-15.27                         Linux kernel image for version 2.6.20 on x86/
ii  linux-image-2.6.20-16-generic          2.6.20-16.32                         Linux kernel image for version 2.6.20 on x86/
ii  linux-image-2.6.22-14-generic          2.6.22-14.47                         Linux kernel image for version 2.6.22 on x86/
ii  linux-image-generic                    2.6.22.14.21                         Generic Linux kernel image

Posted by: SXI ADMIN

The author is the creator of SXI LLC and a seasoned sysadmin, DevOps engineer, and a trainer for the Linux operating system/Unix shell scripting. Get the latest tutorials on SysAdmin, Linux/Unix and open source topics via RSS/XML feed or weekly email newsletter.