The Linux kernel is the core Ubuntu Linux, as well as all other Linux distributions. In this tutorial you will learn how to remove old kernels from Ubuntu Linux system.
Like the rest of the system components, the Linux kernel also gets updated every once in a while. When the kernel is updated on Ubuntu, the operating system will keep some old kernels lying around, in case there is a problem with a new kernel and you need to revert to an older one.
This is a nice feature, although the old kernels can take up storage space. In this tutorial, we will show you how to view the old kernels installed on your Ubuntu system, and also how to remove them.
In this tutorial you will learn:
- How to remove all old kernels with
- How to remove a specific kernel with
- How to view a list of all installed kernels
- How to view kernel version currently in use
- How to upgrade to the lastest Ubuntu kernel
|Category||Requirements, Conventions or Software Version Used|
|System||Any Linux distro|
|Other||Privileged access to your Linux system as root or via the
|Conventions||# – requires given linux commands to be executed with root privileges either directly as a root user or by use of
$ – requires given linux commands to be executed as a regular non-privileged user
How to remove old kernels from Ubuntu
Ubuntu installs new kernels whenever you do a full system upgrade. The new kernel will not be immediately usable, but after a reboot, your system will boot into the new kernel that was downloaded. As mentioned before, the old kernel will stick around in case there is a problem with the new one.
To upgrade your kernel on Ubuntu, you would use the following two
apt commands and then reboot:
$ sudo apt update $ sudo apt full-upgrade $ reboot
To see a list of your Linux kernels on Ubuntu, execute the following
$ sudo dpkg --list | egrep 'linux-image|linux-headers'
At the start of each line, you will see a few letters. This is a two letter abbreviation, with the first letter indicating the desired package state, and the second letter indicating the current package state. We will keep things simple and just tell you what the abbreviations mean:
- ii – indicates packages that are currently installed
- iU – package has been unpacked and will be used next reboot
- rc – package already removed, but the configuration files are still present
To see which Linux kernel your Ubuntu system is currently running, you can run the
$ uname -r 5.13.0-35-generic
Next, let’s look at how to remove these older kernels and their configuration files:
- The recommended method to remove old kernels on Ubuntu is with the
aptpackage manager. The following command will remove old kernels, as well as lingering software packages that are no longer required on your system. It is a good idea to occasionally run this command just to free up disk space.
$ sudo apt autoremove --purge
Note that this command will still keep one old kernel, along with the newest one that Ubuntu is currently running.
- You can manually remove one or more of the kernels with an
aptcommand. Use the
dpkgcommand shown earlier in order to get a list of kernels that you can remove. The following Linux kernel is just an example.
$ sudo apt purge linux-image-5.8.0-50-generic
In this tutorial, we saw how to remove old kernels from Ubuntu. We also learned how to view which kernels are currently installed, and why this feature is implemented into Ubuntu in the first place. Deleting old kernels can free up a little disk space, and running the
apt autoremovecommand is a good habit just to keep a clean system and remove unused packages.