How to: Linux delete or remove kernel

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Q. I have multiple versions installed and I need to save disk space. I am using Cent OS Linux. How can I delete or remove a Linux kernel from my Linux distribution ?

A. Linux Kernel and related files are stored in following locations:
=> /boot – Stores actual kernel and related file such system man and initrd images,

=> /etc or /boot/grub – Stores grub.conf file (most distro use /boot/grub these days).

=> /iib/modules/KERNEL-VERSION/* – Linux device drivers (modules)

If kernel is installed using binary package system such as rpm, yum, up2date, apt-get etc you can remove with following commands:

Rpm based distro – Red Hat/CentOS/Fedora Core/Suse Linux

First find out all installed kernel version with following command:
# rpm -qa | grep kernel-smp
or
# rpm -qa | grep kernel
Output:

kernel-smp-2.6.9-42.EL
kernel-smp-2.6.9-42.0.3.EL
kernel-smp-2.6.9-42.0.8.EL

I’ve total 3 different kernel installed. To remove kernel-smp-2.6.9-42.EL type command:
# rpm -e kernel-smp-2.6.9-42.EL
OR
# rpm -vv -e kernel-smp-2.6.9-42.EL

.deb based distro – Debian or Ubuntu Linux

Again find out all installed kernel version:
$ dpkg --list | grep kernel-image
Output:

ii  kernel-image-2.4.27-2-386   2.4.27-10sarge1             Linux kernel image for version 2.4.27 on 386
ii  kernel-image-2.6.8-2-686    2.6.8-16sarge1              Linux kernel image for version 2.6.8 on PPro

Now remove kernel-image-2.4.27-2-386 with apt-get command itself:
# apt-get remove kernel-image-2.4.27-2-386
OR
$ sudo apt-get remove kernel-image-2.4.27-2-386

If you have custom compiled kernel you need to remove following files/dirs:

  • /boot/vmlinuz*KERNEL-VERSION*
  • /boot/initrd*KERNEL-VERSION*
  • /boot/System-map*KERNEL-VERSION*
  • /boot/config-*KERNEL-VERSION*
  • /lib/modules/*KERNEL-VERSION*/
  • Update grub configuration file /etc/grub.conf or /boot/grub/menu.lst to point to correct kernel version.

Caution: Removing working kernel may result into unstable / non- bootable Linux server system.

Posted by: Vivek Gite

The author is the creator of nixCraft 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.

20 comment

  1. i want to remove linux from my system but unable to do so…i formatted the hard disk my making it a slave.but still linux kernel is there and i m getting error message “kernel panic-not syncing:attempted to kill init”..can someone know the solution to completely remove the linux

  2. My Ubuntu system only returns searches by “linux-image”, not “kernel-image”.
    This is most likely due to changes made since this was written.

  4. can any one tell me how to delete linux kernel(vmlinuz).
    and how to ovrride linux kernal with vista kernal.

  7. I have just successfully removed a Centos 5.4 v2.6.18 kernel that I installed yesterday. This kernel was installed using “make install”. After deleting /boot/*KERNEL-VERSION*, I found that I had two stale links in /boot:
    System.map -> /boot/System.map-*KERNEL-VERSION*
    vmlinuz -> /boot/vmlinuz-*KERNEL-VERSION*

    I replaced these links with links to the files that match the default kernel in grub.conf

  8. I have installed kernel2.6.32. After that I am enable to boot the system using the kernel 2.6.32. So I want to remove the kernel2.6.32. But i ont know how to remove kernel from the system. please help me!!!!!!!

    1. 1) First check the current kernel version running on your host machine
      uname -r
      2) List all the kernels installed in the host
      rpm -qa kernel // you can see all the kernels including the one you want to remove
      3) Uninstall the kernel which you want to remove
      rpm -e kernel-2.6.32-xxx.xxx –nodeps
      4) Check if it is uninstalled or not
      rpm -qa kernel

  9. i have make a partition on my windows and i want to remove linux 5.0 so is possible without formatting. I f possible then how, can u tell me its very urgent?

  11. how to clean user space…?
    i tried to compile linux-2.6.26 module after make menucofig executed it shows user space full warning please tell me some answer……!
    advance

  15. Thanks for this, it helped me run through the removal of current kernel by switching the student to edit grub to from entry , and then remove the current one so he could actually see the “New Kernel” update stuff.

  16. I have compiled latest linux kernel 3.11 rc2 on opensuse 12.3 which by default had 3.7 kernel. i have compiled latest kernel 3 times, due to applying btrfs patches (for my project), now latest compiled kernel’s entries are in grub loader, but when new kernel is loaded it is not working properly. so i loaded into default kernel and saw this article and tried to remove custom compiled kernel and entered 1st command
    # rpm -qa | grep kernel-smp
    In o/p there is no entry for 3.11 kernel.
    what to do now ?
    Please help.

  17. It helped me very much!
    I had update from fedora 21 to 22, it worked
    but after that i had 2 other
    unnecessary kernel
    This page helped me very well,
    to remove these

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