How do I remove old kernel versions to clean up the boot menu?

Question

Every time I install a new Linux kernel, it gets left in the grub_config, making the boot menu longer each time.

I know I can manually search through the installed packages and remove them.

Does Ubuntu provide any easier way to clean them up or keep them from showing in the boot list?

Answer 1

11.10 and newer versions of Ubuntu

GRUB2 and its display of all kernels

The latest versions of Grub2 installed in Ubuntu automatically display the latest kernel and hides the older kernels that you may have installed.

If you do not see your grub - then remember to press Shift whilst booting.

As you can see, only the latest kernel is displayed.

If you select the option shown (press Enter) then all the old kernels become visible and available to boot from.

How to permanently delete older kernels

First boot with the latest available kernel.

There are a number of ways to delete old kernels. Personally, I wouldn't touch Computer Janitor since this is acknowledged to break your computer with its suggestions.

synaptic

An alternative is Synaptic (sudo apt-get install synaptic)

search for linux-image, right-click a kernel and choose complete removal and finally click the Apply button to delete the kernel.

Repeat the search but this time for linux-header - you can delete the associated headers for the kernel image chosen previously.

Synaptic though will not attempt to verify what you are trying to remove... you could inadvertently delete your newest kernel - or even delete all of your kernels via this tool leaving you with an unbootable Ubuntu!.

Remember to check which kernel you are using type:

uname -r

The result would be similar to:

Remember the result and the number - make sure you don't delete the corresponding image or header.

Ubuntu-tweak

IMHO, the best GUI tool is Ubuntu-Tweak

It is not available from the standard repositories. To install in 13.10 and older versions you need to use the author's PPA:

sudo add-apt-repository ppa:tualatrix/ppa
sudo apt-get update
sudo apt-get install ubuntu-tweak

In Ubuntu 14.04+ you have to download .deb file from official website and install it using Software Center or manually.

Choose the options shown by the arrows.

Select both the headers and image with the same version number.

It will not allow you to delete the current kernel you are booted with since the current kernel is not displayed.

Recommendation

My recommendation is to keep at least two or preferably three kernels including the latest. The reason for the recommendation is that you will have at least one/two other kernels to boot with, if for what-ever reason the latest kernel you are unable to boot with or introducing a regressed capability such as broken wireless.

Answer 2

Open terminal and check your current kernel:

uname -r 

DO NOT REMOVE THIS KERNEL!

Next, type the command below to view/list all installed kernels on your system.

dpkg --list | grep linux-image 

Find all the kernels that lower than your current kernel. When you know which kernel to remove, continue below to remove it. Run the commands below to remove the kernel you selected.

sudo apt-get purge linux-image-x.x.x.x-generic 

Finally, run the commands below to update grub2

sudo update-grub2 

Reboot your system.

Answer 3

My one-liner to remove old kernels (this also frees up disk space)

dpkg --list | grep linux-image | awk '{ print $2 }' | sort -V | sed -n '/'`uname -r`'/q;p' | xargs sudo apt-get -y purge

Explanation (remember, | uses the output of the previous command as the input to the next)

• dpkg --list lists all installed packages
• grep linux-image looks for the installed linux images
• awk '{ print $2 }' just outputs the 2nd column (which is the package name)
• sort -V puts the items in order by version number
• sed -n '/'`uname -r`'/q;p' prints the lines before the current kernel
• xargs sudo apt-get -y purge purges the found kernels

Unwinding the sed invocation:

• -n tells sed to be quiet
• `uname -r` outputs the current installed kernel release - we include it in backticks so that the output is includes as part of the command (you might also see this as $(uname -r)
• /something/q says stop when you match 'something' (in this case, something is output of uname -r) - the / surround a regular expression
• p is print
• the ; is the command separtor, so /something/q;p says quit when you match something, else print

altogether, sed -n '/'`uname -r`'/q;p' is print the lines until it matches with the current kernel name.

If you're paranoid (like me), you can make the last part xargs echo sudo apt-get -y purge so that the command to purge the old kernels is printed, then you can check that nothing unexpected is included before you run it.

---

Modified version to remove headers:

dpkg --list | grep 'linux-image' | awk '{ print $2 }' | sort -V | sed -n '/'"$(uname -r | sed "s/\([0-9.-]*\)-\([^0-9]\+\)/\1/")"'/q;p' | xargs sudo apt-get -y purge
dpkg --list | grep 'linux-headers' | awk '{ print $2 }' | sort -V | sed -n '/'"$(uname -r | sed "s/\([0-9.-]*\)-\([^0-9]\+\)/\1/")"'/q;p' | xargs sudo apt-get -y purge

Note: the sed invocation is modified. "$(uname -r | sed "s/\([0-9.-]*\)-\([^0-9]\+\)/\1/")" extracts only the version (e.g. "3.2.0-44") , without "-generic" or similar from uname -r

---

All-in-one version to remove images and headers (combines the two versions above):

echo $(dpkg --list | grep linux-image | awk '{ print $2 }' | sort -V | sed -n '/'`uname -r`'/q;p') $(dpkg --list | grep linux-headers | awk '{ print $2 }' | sort -V | sed -n '/'"$(uname -r | sed "s/\([0-9.-]*\)-\([^0-9]\+\)/\1/")"'/q;p') | xargs sudo apt-get -y purge

Answer 4

Removing Entries from Grub 2 Entries should be removed by editing or removing files in the /etc/grub.d folder. The /boot/grub/grub.cfg file is read-only and should not normally require editing.

Too Many Kernels?

• If you are not sure of the kernel you are currently using, in a terminal type uname -r.

• Kernels removed via APT (Synaptic, "apt-get remove", etc.) will automatically update grub.cfg and no user action is required.

• A great tool for removing kernels (and menu entries) is Ubuntu-Tweak, a safe and easy-to-use GUI app.

• Install ubuntu tweak

• Ubuntu-Tweak will be available under Applications > System Tools.

Remove Older Kernel Entries

• Select "Package Cleaner" on the left and "Clean Kernel" from the right panel.

• Press the "Unlock" button at the lower right, enter your password.

• Select from the displayed list the kernel images and headers you wish to remove. The kernel in use is not listed.

• Press the "Cleanup" button at the lower right to remove the selected kernel images and headers.

Remove Operating Systems from the Grub menu

• Other Operating Systems which have been removed from the computer will also be removed from the menu once "update-grub" is run as root.

• Menu items are placed on the Grub2 menu by scripts. If you don't want other Operating Systems to be entered in the menu, disable /etc/grub.d/30_osprober

• Run this command to stop the script from running
  sudo chmod -x /etc/grub.d/30_os-prober

• DISABLE_30_OS-PROBER='true' in /etc/default/grub

Remove Memtest86+ from the Grub Menu
sudo chmod -x /etc/grub.d/20_memtest86+

• Run the update-grub command to allow the changes to be incorporated in grub.cfg

Source

Note: After kernel updates a new entry is added to the GRUB menu.You can remove the older one if you want.However, most experienced users will advise you to keep at least one spare entry in case something goes wrong with an upgrade and you need to boot an older kernel version for troubleshooting purposes.

Alternate way to remove Kernel entries (prior to 10.04)

for GRUB not GRUB2

startupmanager

You can find it under System>>Administration>>

You see in the second screenshot you can select how many kernels to show? I generally just keep it on 1, but when I get a kernel upgrade I always change it to 2 before restarting so I can select the older kernel if the new kernel has problems with my hardware. Once I know the new kernel is working well I change it back to 1.

Answer 5

Purely commandline, this will remove all but the current and second most current (via the "-2" in the head command below):

OLD=$(ls -tr /boot/vmlinuz-* | head -n -2 | cut -d- -f2- |
    awk '{print "linux-image-" $0 " linux-headers-" $0}' )
if [ -n "$OLD" ]; then
    apt-get -qy remove --purge $OLD
fi
apt-get -qy autoremove --purge

Answer 6

10.04 GUI Method

Computer Janitor can clean up old kernels and I believe is installed by default in Ubuntu (but not Kubuntu).

GRUB 1, if you're using that, has an option in /boot/grub/menu.lst to specify how many kernels it should show at a maximum. GRUB 2, as far as I can tell, does not.

Answer 7

You can follow the Using the "unattended-upgrades" package section of Automatic Security Updates article on Ubuntu Wiki to perform this.

You need to change the following line in /etc/apt/apt.conf.d/50unattended-upgrades file;

//Unattended-Upgrade::Remove-Unused-Dependencies "false";

with

Unattended-Upgrade::Remove-Unused-Dependencies "true";

to automatically remove old packages, including kernels.

Also remove or comment the line

"^linux-image.*"; 

in the "NeverAutoRemove" section of the file /etc/apt/apt.conf.d/01autoremove.

Answer 8

To figure out what kernels and headers are installed use

dpkg -l | grep linux-image

dpkg -l | grep linux-headers

You can then remove them one by one or together, just make sure to keep the most recent.

There are also some handy commands and scripts to automate the removal.

http://ubuntuforums.org/showthread.php?t=1658648

The following claims to remove all unused kernels and headers:

dpkg -l 'linux-*' | sed '/^ii/!d;/'"$(uname -r | sed "s/\(.*\)-\([^0-9]\+\)/\1/")"'/d;s/^[^ ]* [^ ]* \([^ ]*\).*/\1/;/[0-9]/!d'|grep -E "(image|headers)" | xargs sudo apt-get -y purge

If you don't ever need old kernels, set that command to run as a monthly cron job.

Answer 9

The fastest/simpler way (Applicable at least since 12.04) possible that already comes with Ubuntu is apt-get. Do the following if you wish to remove all older kernel versions that are not in use (Except the previous one that you are no using. This is to make sure that if the current kernel version fails in some way, you have a way to go back to a previous state). Do the following:

sudo apt-get autoclean

This will eliminate any old files (Including kernel versions) you may have. Note that if you have many old versions, it will take a while since it has to make sure that removing the kernel version has no issues. For me, removing the last 12 kernel versions took about 2 minutes. You can also do the following:

sudo apt-get clean

Which will eliminate everything downloaded and stored in the cache folder of apt. Lastly you have:

sudo apt-get autoremove

which would check for any unused packages and remove them if necessary. This is great for those libraries and dependency packages that are no longer needed byt any app installed.

Answer 10

In order to remove older Linux image kernels, first boot in the kernel you want to keep.

You can also check the kernel version using command uname -r so that you don't remove the wrong one by mistake.

Now go to synaptic package manager and search for linux-image and remove the older versions except the one shown by upper command. Generally I prefer to go with the latest one.

Now when you restart you'll see a more clean grub menu.

Answer 11

There is a command called purge-old-kernels that can be used to purge extra kernels. It will keep 2 latest kernels and the current one by default. The package has a few dependencies, though. The command is available in bikeshed Ubuntu package (available in universe repository) of Ubuntu Trusry and Wily. The command is also available in byobu PPA repository

I made another script. It aims to let user purge some kernels that are older than the currently used one. You can set by an option, how many older kernels it keeps. This has the advantage that it will not purge any newer kernels that may exist e.g when system has not been booted after installing some new kernel(s). My script also purges more kernel related packages matching the kernel version to be purged. And it does not remove kernels that are needed for getting updates in the repository.

The script is available at GitHub.

Save the script e.g. as purge-older-kernels, make it executable by running chmod a+x ./purge-older-kernels in the directory. Then you can see its usage by running ./purge-older-kernels -?. If you want to use the script like a command, copy the script in "/usr/local/bin". Actual removing requires superuser privileges, i.e. use of sudo.

If you just want to purge the kernels (and the related packages) that are older than the currently used kernel, you could use this script.

There is also an Ubuntu documentation page that I have contributed to concerning removing old kernels here.

Answer 12

You could install ubuntu-tweak and then Go to Applications -> System tool -> ubuntu tweak and

click package cleaner and clean kernels. it does not show the currently used kernel so you will always be safe.

Answer 13

You can uninstall the old kernels (linux-image-... packages) using Synaptic, and that will remove them from the boot menu. Take care not to remove the running kernel (you can check its version with uname -r).

Bear in mind that having a one or two older versions can help you troubleshoot, should something go wrong.

Alternatively, you can edit/remove the entries manually (gksu gedit /boot/grub/grub.cfg), but they will be re-generated when you update to a newer kernel. If you are thinking about removing recovery mode options - don't. They can come in handy if you break something which prevents you from booting.

---

Refer to this page.

Answer 14

I find this to be the easiest and quickest way. It keeps the latest kernel as well as two more:

sudo apt-get -y install bikeshed
sudo purge-old-kernels

To change the number of additional kernels that are kept:

sudo purge-old-kernels --keep 3

Answer 15

Personally, I like using Synaptic. It makes me feel more secure about what's going on. The only app I've used that has an option to remove old kernels is Ubuntu Tweak.

How to remove the kernels you are not using:

• Open UbuntuTweak
• Click on 'Package Cleaner' under 'Applications' in the left-hand pane
• On the right side of the 'cleaning view' press 'Clean Kernels'
• Select all kernels - I think the one in use is not listed but just in case check running uname -a in a terminal

Answer 16

ailurus has the feature of removing old kernels as well as unused configurations. I personally remove it manually from synaptic. You can install ailurus from getdeb as well as ppa

Answer 17

An easy way to get rid of almost all obsolete packages, packages no longer in any package list, along with obsolete kernels is to do one of the following:

dpkg --purge $(aptitude search ?obsolete)

However, this will miss packages that are still recommended by other packages, and the -R/--without-recommends argument does not resolve this problem.

dselect after switching sort mode with 'o' will show all obsolete packages including the ones aptitude misses, but some people don't like using it.

Answer 18

The accepted answer using sed to remove older kernels permanently has some flaws, if someone has not rebooted the computer after upgrading kernel the command will remove the newer kernel too.

Here is an alternate solution that will consider all situations to remove actual older kernels only:

#!/bin/bash
kernels=( $(grep -Po "^linux-image-[^-]+-[^-]+-generic\b" < <(dpkg --get-selections)) )
cur_rel=$(grep -Po ".*(?=-[a-z]*$)" < <(uname -r))

for kernel in "${kernels[@]}"; do
    ker_rel=$(grep -Po "[0-9].*(?=-[a-z]*)" <<< "$kernel")
    dpkg --compare-versions "$ker_rel" gt "$cur_rel" && echo "Please Restart your computer first" && break
    dpkg --compare-versions "$ker_rel" lt "$cur_rel" && sudo apt-get remove "$kernel"
done

If you have any version that is newer than the current one this will give you a warning to restart you computer first. Also note that the older kernels are preserved due to a good reason which is if you somehow mess up your current kernel making your system unstable then you should be able to boot into any older kernel.

Answer 19

Next time, when removing old kernels open a Terminal and use this command: sudo apt-get autoremove linux-headers-2.6.38-10-generic

You can use Synaptic to get the exact name of the kernel that you intend to delete. Just open Synaptic and search for "linux-headers" and then select which kernel entry you want to remove. The relevant entry will be tagged with "-generic" at the end.

To clear out any unused (left over) dependencies throughout the system use this command by itself: sudo apt-get autoremove

Answer 20

here is a rough outline of what I did, careful as I am no expert in linux, be sure you know what you are doing and have backed up any files you are modifying.

gedit /boot/grub/grub.cfg

then find the entries you want to keep, we will highlight and copy them

cd /etc/grub.d
ls

you'll see a list of files like 10_linux and 30_os-prober

sudo chmod -x 10_linux

this will stop form auto adding all the linux entries into the grub boot menu.

gksudo gedit 40_custom

open the custom boot menu file, then go back to grub.cfg (which should still be open in gedit), and copy the entries you want to keep... such as

menuentry "My Default Karmic" {
  set root=(hd0,1)
  search --no-floppy --fs-uuid --set cb201140-52f8-4449-9a95-749b27b58ce8
  linux /boot/vmlinuz-2.6.31-11-generic root=UUID=cb201140-52f8-4449-9a95-749b27b58ce8 ro quiet splash
  initrd /boot/initrd.img-2.6.31-11-generic
}

paste them into 40_custom, and then save it.

sudo chmod 755 40_custom

makes it executable, then finally we update grub which will change the grub.cfg file:

sudo update-grub

Now, BEWARE, if you update your kernel or OS, your boot menu probably will not update... you'll have to do that manually. But doing this procedure will let you customize the boot menu a bit more, such as remove the kernel version and just put the ubuntu name... i.e. Ubuntu Lucid 10.04, etc...

Hope someone finds this helpful, as it took me a while to figure out... didn't see this solution anywhere...

Answer 21

Install the synaptic package manager and go down to the filters tab (I think filters, if not try all 5) and select "local". This will show you orphaned packages on your system, such as the kernels. After you uninstall them, run update-grub. That command updates the list of boot options for grub.

If this fails, you can always try apt-get remove linux-image-version-generic.

Answer 22

Based on a previous answer by David Kemp, the following script will purge all headers and images except for the last 2 versions.

#!/bin/sh
# This script assumes that the installed linux-image and linux-headers packages
# share the same versions (i.e. if a linux-image version number is installed,
# the corresponding linux-headers package will also be installed, and vice
# versa.)

SECONDTOLASTVER=$(dpkg --list | grep linux-image | awk '{ print $2 }' | sort -r -n | sed '/^[^0-9]\+$/d' | sed 's/^.*-\([0-9\.]\+-[0-9]\+\).*/\1/' | uniq | sed -n 2p)

# get a list of package names matching the argument passed to the function, and
# return only those package names which should be removed
get_pkgs_to_remove_matching () {
    if [ -n "$SECONDTOLASTVER" ]; then
        echo $(dpkg --list | grep $1 | awk '{ print $2 }' | sort | sed -n '/'"$SECONDTOLASTVER"'/q;p')
    fi
}

echo $(get_pkgs_to_remove_matching linux-image) $(get_pkgs_to_remove_matching linux-headers) | xargs sudo apt-get -y purge

Answer 23

The following string of commands will purge any installed linux kernels except the currently running one (grep -v uname -r) and the lastest available kernel (dpkg -l | .... | tail -1):

dpkg -l | grep -E linux-image-.*-generic | cut -d ' ' -f3 | grep -v `dpkg -l | grep -E linux-image-.*-generic | cut -d ' ' -f3 | tail -1` | grep -v `uname -r` | xargs apt-get -y purge

I use this to keep desktop's boot volumes relatively clean, but in a server situation you'd probably want to expand the logic and write some additional scripting to maintain a list of the last X kernels the server has booted.

Something like a startup script that does:

uname -r >> /root/bootedkernels
cat /root/bootedkernels | sort -u | tail -3 > /root/bootedkernels # Keep the last 3 booted kernels

and then use:

dpkg -l | grep -E linux-image-.*-generic | cut -d ' ' -f3 | grep -vf /root/bootedkernels | grep -v `dpkg -l | grep -E linux-image-.*-generic | cut -d ' ' -f3 | tail -1` | grep -v `uname -r` | xargs apt-get -y purge

Answer 24

To have a bit more control over which versions to keep, explicitly select the ones you want to remove. For instance if you want to remove kernel versions 3.2.0.[49-53], use a simple for loop:

for k in 49 51 52 53 ; do aptitude remove --purge linux-image-3.2.0-${k}-generic ; done

Adjust the list of kernel versions to fit.

Answer 25

Try this. Run it as root.

Save this script as, say ./keep-n-kernels.sh

Pass, as a command line argument, the number of most recent kernels you want to preserve.

    
#!/bin/bash

# pass n as a command line argument, and it will find all the installed
# kernels and keep only the n most recent ones => uninstall all older ones

# dpkg -l 'linux-*' | sed '/^ii/!d;/'"$(uname -r | sed "s/\(.*\)-\([^0-9]\+\)/\1/")"'/d;s/^[^ ]* [^ ]* \([^ ]*\).*/\1/;/[0-9]/!d'
# this command gives the list of all packages EXCEPT for the latest kernel.
# source : https://help.ubuntu.com/community/Lubuntu/Documentation/RemoveOldKernels

n=$1

# find the installed kernel versions :
# dpkg-query -W -f='${Version}\n' 'linux-image-*' | grep . | sort -n
# gives version numbers, one in each line
# dpkg-query -W -f='${Version}\n' 'linux-image-*' | grep . | sed 's/\...$//g' | grep -v '\...$'| sort -u
# gives only the ones that appear in linux-image

# suffix, e.g. -generic-pae
# the kind of kernel you boot into
suffix=$(uname -r | sed 's:^[0-9]\.[0-9]\.[0-9]\-[0-9]\{2\}::g')

command="apt-get purge "

for version in $(dpkg-query -W -f='${Version}\n' 'linux-image-*' | grep . | sed 's/\...$//g' | grep -v '\...$'| sort -u | head -n -${n})
do
    command=${command}"^linux-image-${version}${suffix} "
done

$command

Sample usage :

# ./keep-n-kernels.sh 4 # launch the apt-get command to remove all but the 4 most recent kernels

If you want [AND AT YOUR OWN RISK], you can add a -y (or a force flag) to the apt-get command and make it non-interactive.

Answer 26

I'm using a KDE desktop, and the easiest option I found was using the kde-config-grub2 application as suggested here: https://www.kubuntuforums.net/showthread.php?58075-remove-old-linux-versions (which I already had installed for setting background image, default boot option, and the like). Next to the drop-down box where you can choose the default entry, there is a "Remove Old Entries" button. Clicking this button presents you with a list of all installed kernels and you can select which ones to remove. When you apply the changes it will use dpkg to actually remove them from the system as well as the GRUB menu.

Answer 27

Just to chime in, you can also issue

apt-get remove linux-{image,headers}-x.y.z-{1,2,...,n}

as root, and the job will be done.

Answer 28

I have a script for this that does not need very fancy string parsing.

Remove headers and images except the current one to release space

sudo apt-get autoremove --purge 'linux-headers-[0-9].*' linux-headers-$(uname -r)+ linux-headers-$(uname -r | cut -d- -f1,2)+ 'linux-image-[0-9].*' linux-image-$(uname -r)+

Answer 29

This is a pure command line solution.

First generate a list of all installed kernel versions except the currently running kernel:

dpkg-query -W -f='${Package}\n' |
  grep -f <(ls -1 /boot/vmlinuz* | cut -d- -f2,3 |
    grep -v $(uname -r | cut -d- -f1,2))

Alternatively generate a list of all installed kernel versions except the last two:

dpkg-query -W -f='${Package}\n' |
  grep -f <(ls -1 /boot/vmlinuz* | cut -d- -f2,3 |
    sort -V | head -n -2)

Examine the list. Make sure the the kernel versions you want to keep are not part of the list. Use the command uname -r to see the version of the currently running kernel.

If you are happy with the results you can use apt-get to remove the packages.

First a dry run (using the first generator as example):

sudo apt-get --dry-run purge $(
  dpkg-query -W -f='${Package}\n' |
    grep -f <(ls -1 /boot/vmlinuz* | cut -d- -f2,3 |
      grep -v $(uname -r | cut -d- -f1,2)))

Then a real run:

sudo apt-get purge $(
  dpkg-query -W -f='${Package}\n' |
    grep -f <(ls -1 /boot/vmlinuz* | cut -d- -f2,3 |
      grep -v $(uname -r | cut -d- -f1,2)))

If you want to automate the process then add the --yes parameter:

sudo apt-get --yes purge $(
  ...)

Answer 30

Backup your GRUB configuration file which is in /boot/grub/grub.cfg which we will need if something goes wrong.

Open Terminal CTRL+ALT+T. You need to be the root. For that :

sudo -i

Now we want to edit the file. For that:

gedit /boot/grub/grub.cfg

You will get GEDIT window.

Now search for ### BEGIN /etc/grub.d/10_linux ###.

After that line you will see the items of your GRUB.

So if we want to remove Ubuntu, with Linux 2.6.32-30-generic from GRUB, Remove the red highlited line in the image.

You should have got the idea of removing items from GRUB.

After editing the file save it.

Do as you like but be careful not to remove other lines.

**

• NOTE

:**

When kernel is updated the /boot/grub/grub.cfg is recreated. So the older kernels will be visible again. You have to do this every time you run the command update-grub and after updating the kernel.

Source (my blog): How to remove a item from GRUB boot menu