minimize.sh: remove kernels with higher versions

[rubo77]

Kernel version is at 5 already.

[rubo77]

On Ubuntu I get a strange behaviour:

# uname -r
5.15.0-56-generic

# dpkg --list | awk '{ print $2 }' | grep 'linux-image-[3-9].*-generic'                                            
linux-image-5.15.0-53-generic
linux-image-5.15.0-56-generic

# dpkg --list | awk '{ print $2 }' | grep 'linux-image-[3-9].*-generic' | grep -v $(uname -r) | xargs apt-get purge
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following additional packages will be installed:
  linux-image-unsigned-5.15.0-53-generic
Suggested packages:
  fdutils linux-doc | linux-source-5.15.0 linux-tools linux-modules-extra-5.15.0-53-generic
The following packages will be REMOVED:
  linux-image-5.15.0-53-generic* linux-modules-extra-5.15.0-53-generic*
The following NEW packages will be installed:
  linux-image-unsigned-5.15.0-53-generic

How could I solve this?

[rubo77]

This script doesn't cause the problem: https://askubuntu.com/a/1409370/34298