Super User is a question and answer site for computer enthusiasts and power users. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I am using CentOS 6.2. In the man page of uname (i.e., man uname), it says:

 -r, --kernel-release
              print the kernel release

 -v, --kernel-version
              print the kernel version

While trying the command, it shows

[max@localhost ~]$ uname -r


[max@localhost ~]$ uname -v

#1 SMP Tue May 15 22:09:39 BST 2012

-v should show the version, right? But where is it showing the version? -r is showing the version detail.

Why is this so?

share|improve this question

This is absolutely normal and expected. kernel-release will always show the actual version number of the used kernel. kernel-version however will print a more specific string with the actual release date. Its format depends on which Linux or Unix distribution it's run on.

You can find an extensive list of examples on Wikipedia. For example, in OS X, the kernel-version will be not only the release number, but also the release date:

Darwin Kernel Version 10.8.0: Tue Jun  7 16:32:41 PDT 2011; root:xnu-1504.15.3~1/RELEASE_X86_64

While the kernel-release is simply the release number:


You can even check /proc/sys/kernel/ for the things uname(2) will look up when it's called by uname(1). This would be:

  • /proc/sys/kernel/version
  • /proc/sys/kernel/osrelease

Don't think too strictly of "version" as just a version number.

share|improve this answer
Obviously the right answer, whether the other poster disagrees or not. – don_crissti Feb 22 at 1:38

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .