How to remove old kernel images

Intro:

Like yourself and all other Debian & derivative users, I needed a way to prune my old Kernels. However, the ones I found on the 'net were almost perfect- they deleted all Kernels except the current ones- but unfortunately they would also remove the LATEST version that I wanted to upgrade to.

Solution:

The below one-liner-there may be more elegant ways to write it- will remove all Kernels except for both the CURRENT and the LATEST Kernels. I eat my own dog food and can say it's tested and known to work on my own inventory of Ubuntu 22.04 hosts:

Test (won't apply changes):

dpkg --list | grep -v $(uname -r) | grep -E 'linux-image-[0-9]|linux-headers-[0-9]' | awk '{print $2" "$3}' | sort -k2,2 | head -n -2 | awk '{print $1}' | xargs sudo apt-get purge 

Apply Changes (-y to the apt-get purge command above):

dpkg --list | grep -v $(uname -r) | grep -E 'linux-image-[0-9]|linux-headers-[0-9]' | awk '{print $2" "$3}' | sort -k2,2 | head -n -2 | awk '{print $1}' | xargs sudo apt-get -y purge 

How it Works:

Part 1: List all kernels & Headers EXCLUDING (grep -V) the current one:

dpkg --list | grep -v $(uname -r) | grep -E 'linux-image-[0-9]|linux-headers-[0-9]'

Part 2: Only print the column with the Kernels & headers from the dpkg --list output

dpkg --list | grep -v $(uname -r) | grep -E 'linux-image-[0-9]|linux-headers-[0-9]' | awk '{print $2" "$3}'

Part 3: Next we sort the list by the 2nd column in ascending numerical order:

dpkg --list | grep -v $(uname -r) | grep -E 'linux-image-[0-9]|linux-headers-[0-9]' | awk '{print $2" "$3}' | sort -k2,2

Part 4: Print list EXCLUDING the last (2) lines which are the Kernel & header for the LATEST Kernel version:

dpkg --list | grep -v $(uname -r) | grep -E 'linux-image-[0-9]|linux-headers-[0-9]' | awk '{print $2" "$3}' | sort -k2,2 | head -n -2

Part 5: After sorting on the 2nd column we print just the Kernel & header package names:

dpkg --list | grep -v $(uname -r) | grep -E 'linux-image-[0-9]|linux-headers-[0-9]' | awk '{print $2" "$3}' | sort -k2,2 | head -n -2 | awk '{print $1}'

Part 6: Finally, after we've built the list which excludes both the CUURRENT and LATEST Kernel versions, we feed it to xargs which chews through each line with apt-get -y purge

dpkg --list | grep -v $(uname -r) | grep -E 'linux-image-[0-9]|linux-headers-[0-9]' | awk '{print $2" "$3}' | sort -k2,2 | head -n -2 | awk '{print $1}' | xargs sudo apt-get -y purge

Conclusion:

There might be more elegant & tighter ways of writing the above, but it does the business. Anyway, hope this saves you- and others- some time-