plonk/README.md

PLONK

PLONK stands for:

PLONK Leaves Only Needed Kernels

It is a small Debian-oriented shell script used to list, simulate and purge old Linux kernel packages.

In short:

old kernels go plonk.

What it does

PLONK helps keeping Debian systems clean by removing old kernel packages while preserving the kernels that are still needed.

It can:

• list old installed kernel packages;
• list kernel packages left in rc state;
• simulate the purge operation before doing anything;
• purge old kernel packages;
• keep a configurable number of installed kernels;
• always keep the currently running kernel;
• avoid removing Debian kernel meta-packages such as linux-image-amd64.

Why

Debian systems can accumulate old kernel packages over time, especially on long-lived servers or frequently updated machines.

Sometimes old kernels are already removed but still appear in dpkg output with rc status, meaning that only residual configuration files are left.

PLONK tries to clean both cases in a conservative way.

Requirements

PLONK requires:

• Debian;
• bash;
• apt-get;
• dpkg-query;
• root privileges when actually removing packages.

It is mainly written and tested with Debian in mind.

Usage

plonk [option]

Available options:

-l | --list      : list old kernel packages
-n | --dry-run   : simulate old kernel packages removal
-r | --remove    : remove old kernel packages
-k | --keep NUM  : number of kernels to keep
-y | --yes       : assume yes when removing packages
-h | --help      : show help and exit

Examples

List old kernel packages and residual rc packages:

./plonk --list

Simulate the purge operation:

./plonk --dry-run

Remove old kernel packages:

sudo ./plonk --remove

Remove old kernel packages and keep three installed kernels:

sudo ./plonk --remove --keep 3

Remove old kernel packages without confirmation:

sudo ./plonk --remove --yes

Recommended workflow

Before removing anything, always run:

./plonk --list

Then run:

./plonk --dry-run

Only after reviewing the output, run:

sudo ./plonk --remove

On production servers, remote systems or machines where rollback matters, keeping more than the default number of kernels is recommended:

sudo ./plonk --remove --keep 3

About rc packages

In dpkg output, packages in rc state are already removed, but their configuration files are still present.

Example:

rc  linux-image-6.1.0-38-amd64  6.1.147-1  amd64  Linux 6.1 for 64-bit PCs

PLONK can purge those residual packages too.

Safety notes

PLONK is intentionally conservative.

It always keeps:

• the currently running kernel;
• at least one additional installed kernel by default;
• the related Debian kernel ABI packages;
• Debian kernel meta-packages.

Still, kernel removal can be risky. Always check the dry-run output before purging packages.

Install

Clone the repository:

git clone <repo-url>
cd plonk

Make the script executable:

chmod +x plonk

Optionally install it system-wide:

sudo install -m 0755 plonk /usr/local/sbin/plonk

Then run:

plonk --help

Name

plonk is both:

PLONK Leaves Only Needed Kernels

and the sound old kernels make when they finally disappear down the drain.

License

• GPL-3.0-or-later.