Purging old kernels

[zurga]

I frequently have to purge old kernels to make space for updates. In view of the following screen grab, I think "linux-image-generic" should be removed, but because of its name format being distinct from the others I am not sure.
I will appreciate it if someone could tell me whether it is safe to remove that item. Many thanks.

$ dpkg --get-selections | grep linux-image
linux-image-3.13.0-68-generic install
linux-image-3.13.0-70-generic install
linux-image-3.13.0-71-generic install
linux-image-extra-3.13.0-68-generic install
linux-image-extra-3.13.0-70-generic install
linux-image-extra-3.13.0-71-generic install
linux-image-generic install

[ian-weisser]

linux-image-generic is not a kernel package; it's a kernel metapackage.

That particular metapackage causes your system to upgrade to a new kernel when released. It contains no kernel files; it pulls in the appropriate kernel package as a dependency.

You can indeed remove the package without immediately damaging your system, BUT your system will no longer automatically upgrade the kernel...including security upgrades. You will need to begin manually tracking and upgrading kernel security upgrades...which also won't save you any space.

The simplest way to save space is to keep the metapackage, and to run 'sudo apt-get autoremove' after each kernel upgrade (or periodically). If you wish to automate that trivial step, the unattended-upgrades pacakge includes a setting to run autoremove every day in the background.

[zurga]

Thank you very much Ian for your explanation. Much appreciation, and it is good to know.

[ptn107]

Pop this in a script and make it easy. It removes all but the current running kernel:

#!/bin/bash

kernel_list=$(dpkg -l | awk '{print $2}' | grep linux-image- | grep -v $(uname -r) | grep -v linux-image-generic)
headers_list=$(dpkg -l | awk '{print $2}' | grep linux-headers- | grep -v $(uname -r | cut -d \- -f 1,2) | grep -v linux-headers-generic)

apt-get purge -y $kernel_list $headers_list
Shove the script in /etc/cron.{daily,weekly}/ and you're good to go