Remove unused kernel images/headers in Ubuntu

The command below removes the image and associated headers of the kernel not currently running. This allows us to reclaim disk space in /boot (especially when created as a separate partition). The kernel version currently running (usually the latest) can be viewed using the command uname -r.

To be sure, upgrade the system first.

sudo apt-get -y update
sudo apt-get -y upgrade
sudo reboot
uname -r

Then remove the old kernel images and headers.

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