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:

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Tutorial details
Difficulty	Easy (rss)
Root privileges	Yes
Requirements	None
Time	1m

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:

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

For example, at the prompt, I type the following on AIX unix to print OS name:
uname
Sample outputs:

AIX

Common uname options

Option	Description
-a	Behave as though the options -m, -n, -r, -s, and -v were specified.
-i	Write the kernel ident to standard output.
-K	Write the FreeBSD version of the kernel.
-m	Displays the machine ID number of the hardware running the system.
-n	Write the name of the system/node to standard output.
-o	This is a synonym for the -s option, for compatibility with other systems.
-p	Displays the architecture of the system processor.
-r	Displays the release number of the operating system.
-s	Write the name of the operating system implementation to standard output.
-v	Write the version level of this release of the operating system to standard output.

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 (brewbuilder@hs20-bc2-3.build.redhat.com) (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:

Video 01: Find The Linux/Unix Kernel Version Command Tutorial

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

Conclusion

We have shown you how to find the version of the Unix and Linux kernel running on your server/desktop/laptop/workstion from the command line. See uname man page here and here for more info.

Category	List of Unix and Linux commands
File Management	cat
Firewall	Alpine Awall • CentOS 8 • OpenSUSE • RHEL 8 • Ubuntu 16.04 • Ubuntu 18.04 • Ubuntu 20.04
Network Utilities	dig • host • ip • nmap
OpenVPN	CentOS 7 • CentOS 8 • Debian 10 • Debian 8/9 • Ubuntu 18.04 • Ubuntu 20.04
Package Manager	apk • apt
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Searching	grep • whereis • which
User Information	groups • id • lastcomm • last • lid/libuser-lid • logname • members • users • whoami • who • w
WireGuard VPN	Alpine • CentOS 8 • Debian 10 • Firewall • Ubuntu 20.04