Clean /boot by removing old kernel packages

clean.md

First check your current version.

uname -a

Then run the following command:

dpkg -l 'linux-*' | sed '/^ii/!d;/'"$(uname -r | sed "s/\(.*\)-\([^0-9]\+\)/\1/")"'/d;s/^[^ ]* [^ ]* \([^ ]*\).*/\1/;/[0-9]/!d'

This command will list all packages that you no longer need. So for every package listed do the following:

sudo apt-get -y purge some-kernel-package