Boot partition is full, running old kernel, new kernels "waiting" - safe to reboot? [duplicate]

Question

This is not a duplicate as suggested above - for why, see the text below.

I have the strange situation that an "old" kernel is running (in fact it is the OLDEST): uname -r

> 4.13.0-43-generic

Using a command to show available kernels I only see NEWER kernels(!):

sudo dpkg --list 'linux-image*'|awk '{ if ($1=="ii") print $2}'|grep -v `uname -r`
linux-image-4.13.0-45-generic
linux-image-4.15.0-24-generic
linux-image-4.15.0-29-generic
linux-image-4.15.0-30-generic
linux-image-4.15.0-32-generic
linux-image-4.15.0-33-generic
linux-image-4.15.0-34-generic
linux-image-extra-4.13.0-45-generic

It looks as if the system never rebooted to "get to the new kernels" - I see for example that in the root dir:

ls -al

lrwxrwxrwx   1 root root    33 Sep 11 06:02 initrd.img -> boot/initrd.img-4.15.0-34-generic
lrwxrwxrwx   1 root root    33 Sep 11 06:02 initrd.img.old -> boot/initrd.img-4.15.0-33-generic
lrwxrwxrwx   1 root root    30 Sep 11 06:02 vmlinuz -> boot/vmlinuz-4.15.0-34-generic
lrwxrwxrwx   1 root root    30 Sep 11 06:02 vmlinuz.old -> boot/vmlinuz-4.15.0-33-generic

which kind of suggests this to me (I'm not an ubuntu guru)...

This is not a duplicate question but a new question because I have no old kernels to delete. Other answers detail deleting old kernels with version numbers less than the current kernel.

The running kernel is the oldest listed. I was worried about deleting kernels newer than the current kernel - between the current kernel and the newest and the kernel that was wanting to be installed - but blocked because of 100% full boot partition.

All answers using "apt" do not work when the boot partition is 100% full so please ignore them :)

From my original question: So I'm tempted to reboot the machine. But is this dangerous - since the boot partition is 100% full. "Normally" I'd delete old kernels etc. to free up space. What's the best/safest way to proceed here?

I ask because it seems I "should" make some space (see Will ubuntu boot if the /boot partition is full?)... but how in this particular case?

---

THIS IS HOW I SOLVED the problem:

In the end as apt autoremove etc. do not work in this situation I followed the hints given here:https://gist.github.com/ipbastola/2760cfc28be62a5ee10036851c654600 (See: "Case II: Can't Use apt i.e. /boot is 100% full")

In my case I deleted a newer kernel by hand to release space in /boot in order to be able to proceed:

cd /boot
ls *4.13.0-45*
rm -rf *4.13.0-45*
df -h
sudo apt-get -f install
sudo apt-get autoremove
sudo update-grub
more grub/grub.cfg
reboot

df -h shows boot no longer 100% full With more grub/grub.cfg you can check if the system is catering for the correct kernels (i.e. whether the update grub worked well)

Answer 1

Run these commands, in that order, one by one and check space every time.

sudo apt autoremove

then

sudo apt autoclean

and if not enough space yet run:

sudo apt clean

and

sudo update-grub

must work.

after reboot in new kernel confirm that the latest kernels are fully installed. by running:

uname -r

and

sudo update-initramfs -u -k all

then run

sudo apt purge $(dpkg -l|egrep 'linux-image-[0-9]|linux-headers-[0-9]'|awk '{print $3,$2}'|grep -v `uname -r|cut -f1,2 -d"-"`|sort -nr|tail -n +4|awk '{ print $2}')

this will remove all old kernels except the one you are using and the latest one.

Edit

Note: You can run sudo update-initramfs -u -k all to confirm that the latest kernels are fully installed, before all these commands.