Remove old kernels automatically

[Tom H]

On Mon, Oct 13, 2014 at 8:59 AM, Andrew Langhorn <andrew at ajlanghorn.com> wrote:
>
> Using sed, uname and apt, I am trying to ensure that all kernels older than
> the current and one behind are uninstalled from my machines. I keep the
> current one, for obvious reasons, and the previous kernel in case I need to
> roll back.
>
> To do this, I'm using `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`, which pipes the output of `uname -r ` to sed,
> ignores any lines beginning with `ii` to ensure installed kernels aren't
> removed, and applies that to the ouput of `dpkg -l 'linux-*`.
>
> This ensures that all previous kernels present are removed.
>
> Can I blacklist the previous one, given that I don't know the name, as it
> may well change?

Your sed command is painful to read! :)

The kernel package corresponding to the currently-loaded kernel is
"linux-image-$(uname -r)".

You can list the installed kernels with "ls -1t /boot/vmlinuz*" and
list the corresponding packages with "ls -t /boot/vmlinuz-* | cut
-d'-' -f2,3,4 | awk '{print "linux-image-"$0}'". Assuming that you're
booted using the latest kernel, you can exclude the first two from
your purge.