If you update your Ubuntu kernel frequently, eventually you will come to the realization that it is taking a lot of space to keep the old versions around on disk. Another annoyance is that your Grub loader will show a very long list. Sure, you can keep them around forever, should you need to recover them, but for most people it’s safe to remove them. You can manually select and remove the packages in Synaptic, but the easiest way I’ve found is to sun the following script instead. It will remove all old kernel version (except the current one!):
dpkg -l 'linux-*' | sed '/^ii/!d;/'"$(uname -r | sed "s/\(.*\)-\([^0-9]\+\)/\1/")"'/d;s/^[^ ]* [^ ]* \([^ ]*\).*/\1/;/[0-9]/!d' | xargs sudo apt-get -y purge
Occasionally, you might also want to follow that with the following to clean up other artifacts too…
sudo apt-get autoremove
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