26

I have old Linux kernel versions that I don't use so I was trying to remove them.

List of installed kernels from dpkg --list | grep linux-image

linux-image-5.4.0-26-generic (5.4.0-26.30)   
linux-image-5.4.0-33-generic (5.4.0-33.37)
linux-image-5.4.0-37-generic (5.4.0-37.41)
7
  • 2
    Does sudo apt autoremove help? Which kernels are you asking about?
    – Pilot6
    Jun 24, 2020 at 12:31
  • 1
    Have you tried sudo apt autoremove? Please edit your question and add all the new information. Also indicate if you installed the kernels manually or something special.
    – user68186
    Jun 24, 2020 at 12:33
  • 1
    These are regular Ubuntu kernels. autoremove should remove them.
    – Pilot6
    Jun 24, 2020 at 12:48
  • Hmmm. Show us complete output. dpkg --list output includes kernels that have already been removed. The first column will indicate which packages are removed (rc) and which are installed (ii).
    – user535733
    Jun 24, 2020 at 13:17
  • There are a couple of excellent kernel removal manager type scripts around. I used the server version from here, for a long time, but now use this one. Note that I can not use autoremove, as it misbehaves when one uses mainline kernels. The manual method becomes tedious when trying to clean up 100 kernels. Jun 24, 2020 at 13:48

7 Answers 7

39

Here are the steps to remove unused kernels.

Check what current kernel You run:

uname -a
Linux blackhole 5.6.13-050613-lowlatency #202005141310 SMP PREEMPT Thu May 14 13:17:41 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

I am running 5.6.13-050613-lowlatency

List all installed kernels in Your OS:

dpkg --list | egrep -i --color 'linux-image|linux-headers|linux-modules' | awk '{ print $2 }'
linux-headers-5.6.11-050611
linux-headers-5.6.11-050611-lowlatency
linux-headers-5.6.13-050613
linux-headers-5.6.13-050613-lowlatency
linux-image-unsigned-5.6.11-050611-lowlatency
linux-image-unsigned-5.6.13-050613-lowlatency
linux-modules-5.6.11-050611-lowlatency
linux-modules-5.6.13-050613-lowlatency

Uninstall kernels You don't need:

sudo apt purge linux-headers-5.6.11-050611  linux-headers-5.6.11-050611-lowlatency linux-image-unsigned-5.6.11-050611-lowlatency linux-modules-5.6.11-050611-lowlatency
7
  • dpkg --list | egrep -i --color 'linux-image|linux-headers|linux-modules' | awk '{ print $2 }'. Really? Doesn't ls -1 /boot/vm* list your kernels including the current one? Jun 24, 2020 at 14:31
  • @PaulBenson Your command does not list packages. So You can't use these names in apt or dpkg to uninstall kernels. Jun 24, 2020 at 16:32
  • 4
    Isn't there an automated way to do that? I have more than 50 kernels installed in the list, many with un tag.
    – staticdev
    Jul 27, 2020 at 15:01
  • While this seems tedious, it appears to be the only viable way. I would have loved to do it automatically, but I am unable to find a nice script for that. My hacky workaround is to use sudo apt-get purge linux-*-*-5.* (feel free to remove one -* to catch some other modules and do the same with 4.*) and manually check the output. This will get the desired packages, but might be too aggressive - i.e. check the output carefully to avoid a system suicide.
    – Betaminos
    Apr 13, 2021 at 7:51
  • Sorry for the double comment, StackExchange won't let me edit the comment after the 5 min mark. I have found this nice script: tecmint.com/remove-old-kernel-in-debian-and-ubuntu (i.e. purge-old-kernels as a script included in the package byobu). This might help, but I have already purged all old kernels so can't test it for now.
    – Betaminos
    Apr 13, 2021 at 8:09
25

You can try out this script

remove_old_kernels.sh

#!/bin/bash
# Run this script without any param for a dry run
# Run the script with root and with exec param for removing old kernels after checking
# the list printed in the dry run

uname -a
IN_USE=$(uname -a | awk '{ print $3 }')
echo "Your in use kernel is $IN_USE"

OLD_KERNELS=$(
    dpkg --list |
        grep -v "$IN_USE" |
        grep -Ei 'linux-image|linux-headers|linux-modules' |
        awk '{ print $2 }'
)
echo "Old Kernels to be removed:"
echo "$OLD_KERNELS"

if [ "$1" == "exec" ]; then
    for PACKAGE in $OLD_KERNELS; do
        yes | apt purge "$PACKAGE"
    done
fi

Run it like this for a dry run:

remove_old_kernels.sh

If all looks good, run it again like this:

sudo remove_old_kernels.sh exec
6
  • Excellent, it worked perfect with PopOS 20.04 Nov 11, 2021 at 16:51
  • headers and modules are also getting deleted other than generic. How to handle that situation?
    – Jinna Balu
    Dec 2, 2021 at 17:51
  • You can change the script to only grep for the linux-image if you really want to keep the others Dec 3, 2021 at 22:05
  • Whenever I run this script, and it deletes an entry, I am getting stuck unable to press a selection on the menu about modifying grub files. Is there a way to go about fixing that? When I do manual delete of a kernel, I am able to make a selection in that menu to proceed. Mar 14 at 8:20
  • 1
    Works like a charm on ubuntu 20.04
    – Andy
    Mar 18 at 15:34
5

Just use this:

sudo apt-get autoremove --purge
4
  • 6
    Note that this command won't remove older kernels only, but any package that is not needed as a dependency of other packages along with its configuration files. Jan 8, 2021 at 12:07
  • @BeastOfCaerbannog, sure, thanks for the clarification. Jan 11, 2021 at 10:24
  • 14
    It doesn't work for 20.04 (upgraded from 18.04, and upgraded from 16.04). I can list the packages, but ubuntu doesn't autoremove old kernels.
    – gavioto20
    Jan 12, 2021 at 17:31
  • @gavioto20 strange, I also used Ubuntu 20.04 and this command did work for removing old kernels? It will only remove kernels that are not actively used. Mar 29 at 16:39
2

To easily remove older versions kernels, e.g. kernels starting from 4.0 and so on.

sudo apt-get purge linux-image-4.*
2
  • Are you sure, that linux-image-4.* will remove "old" linux-image-5.4.xxx kernel images? Aug 30, 2020 at 9:34
  • 3
    Ofcourse not, how do you expect that to remove kernels with a starting 5. You can update command accordingly. I just gave an example. For linux-image-5.4.xxx use sudo apt-get purge linux-image-5.4.* and so on. Sep 4, 2020 at 7:14
0

autoremove will only remove packages that are automatically installed. If you ever updated or added a kernel package manually autoremove will not remove it. If you ever "held" a kernel version autoremove will not remove it. If you're wondering why Ubuntu is filling up your boot partition with kernels you no longer use it's likely one of these two reasons.

# Unhold all packages
dpkg --get-selections | grep hold | awk '{ print $1, "install" }' | dpkg --set-selections

# Mark all "manually installed" kernel packages as "automatically installed"
for f in $(apt-mark showmanual | grep linux-); do
    apt-mark auto $f
done

# Remove all packages that are no longer needed
apt-get -y autoremove --purge
0

An update to @alex Burdusel's script would be the following:

#!/bin/bash
# Run this script without any param for a dry run
# Run the script with root and with exec param for removing old kernels after checking
# the list printed in the dry run

uname -a
IN_USE=$(uname -a | awk '{ print $3 }')
echo "Your in use kernel is $IN_USE"

OLD_KERNELS=$(
    dpkg --list |
        grep -v "linux-headers-generic" |
        grep -v "linux-image-generic" |
        grep -v "linux-image-generic" |
        grep -v "${IN_USE%%-generic}" |
        grep -Ei 'linux-image|linux-headers|linux-modules' |
        awk '{ print $2 }'
)
echo "Old Kernels to be removed:"
echo "$OLD_KERNELS"

if [ "$1" == "exec" ]; then
    for PACKAGE in $OLD_KERNELS; do
        yes | apt purge "$PACKAGE"
    done
fi

This solves the issue that it tries to delete the following packages:

linux-headers-generic
linux-image-generic
linux-headers-5.17.5-76051705 # if 5.17.5-76051705-generic is the current kernel
-2

Not one of these worked for me.

Had to use:

sudo dpkg --purge linux.modules-extra-5.4.0-84.94
0

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