~ on nobe4

Nix RPi Bootstrapping

Sun, 03 May 2026 00:00:00 +0000

I can never remember how to set up a Raspberry Pi. Every time I flash an SD card, I end up searching for the same wifi configuration, the same SSH setup, the same boot options.

During my recent exploration of Nix, this felt like an immediate candidate for improvement: the whole configuration lives in code, and rebuilding is one command.

This post covers getting NixOS onto an RPi from scratch, and the problems I hit while deploying updates to it. It is simplified for clarity and covers three areas: building a minimal bootstrap image, handling secrets with agenix, and deploying updates over SSH.

Nix bin alias

Wed, 18 Feb 2026 16:08:07 +0100

In one of my previous post, I explored how to use ln to link files across a NixOS system. The two initial needs were to link configuration files, and create a binary alias.

I tend to install gojq and use it as jq, it makes more sense to me to have a consistent experience between the CLI and library. I have not yet suffered from this choice, despite my intense jq usage.

In this post, we’ll use it to explore how to create a direct link to the gojq binary. The logic can be applied to any other binary of your choice.

Nix-Darwin shell override

Sat, 14 Feb 2026 17:24:28 +0100

All code snippets are simplified for clarity.

Moving aliases to Nix

I recently decided to move my shell aliases, and ZSH options to Nix.

There are predefined Nix options for this, all under programs.zsh and programs.bash.

And since I use the same aliases for zsh and bash, here’s the configuration I came to:

packages/shell/aliases.nix

{ lib, pkgs, ... }:
{
 "ls" = "ls --color=auto";
 "ll" = "ls -la";
}
// lib.optionalAttrs pkgs.stdenv.isDarwin {
 "kitty" = "$HOME/Applications/kitty.app/Contents/MacOS/kitty";
}

packages/shell/shell.nix

{ lib, pkgs, ... }:
let
 shellAliases = import ./aliases.nix { lib = lib; pkgs = pkgs; };
in
{
 programs.zsh = {
 enable = true;
 setOptions = [ "ALWAYS_TO_END" ];
 shellAliases = shellAliases;
 };

 programs.bash = {
 enable = true;
 shellAliases = shellAliases;
 };
}

And I can import shell.nix wherever needed, so far so good.

When ln is not idempotent

Wed, 04 Feb 2026 18:02:56 +0100

TL;DR: ln -T

I was refactoring more my Nix config, and specifically replacing my link farm with nix as described in my previous post.

When I noticed that links were being created in the wrong places. I would run ln more than once and would get links in random locations:

$ ln -vfs "$DOTFILE_FOLDER/nvim/" "$HOME/.config/nvim"
'/home/nobe4/.config/nvim' -> '/home/nobe4/dev/nobe4/dotfiles/nvim'

$ ls -la "$HOME/.config/nvim"
lrwxrwxrwx 1 nobe4 users 35 Feb 4 20:12 /home/nobe4/.config/nvim -> /home/nobe4/dev/nobe4/dotfiles/nvim
# all good!

# do some testing ...

$ ln -vfs "$DOTFILE_FOLDER/nvim/" "$HOME/.config/nvim"
'/home/nobe4/.config/nvim/nvim' -> '/home/nobe4/dev/nobe4/dotfiles/nvim'
# uh, what now?

$ ls -la $DOTFILE_FOLDER/nvim/nvim
lrwxrwxrwx 1 nobe4 users 35 Feb 4 20:12 /home/nobe4/dev/nobe4/dotfiles/nvim/nvim -> /home/nobe4/dev/nobe4/dotfiles/nvim
# what the hell

In a simplified form:

Nix ln, the wrong ways

Sun, 25 Jan 2026 00:00:00 +0000

TL;DR: don’t do this, everyone suggests using home-manager, or a non-Nix solution.

In the exploration of porting my configuration to Nix, the next step was to manage all the links. This article shows a couple of wrong ways to do it, they are still good learning paths, hence this writing.

Unless otherwise specified, all code examples are simplified for clarity.

Current configuration

Whenever I need to link a new file, I add a line in:

Nix packaging

Mon, 12 Jan 2026 00:00:00 +0000

I have been using Nix for a couple of month, from a purely consumer perspective. In all tools that I wanted to master, producing is a great teaching tool, sometimes more than consuming.

In that effect, I wanted to see how I could install bat, without using the predefined package.

The plan

Download the source code

This is achieved with fetchFromGitHub.
Compile the rust binary

This is achieved with buildRustPackage.

Great Flag Unification

Wed, 26 Nov 2025 00:00:00 +0000

If there’s something I like, it’s simplicity. If there’s something that’s not simple, it’s the flags of the world. In this post I try to redesign flags in a simplified way, using only 4 basic shapes: rectangles, circles, half-circles, and triangles.

Each flag operates on a 12 ×12 grid, which works surprisingly well for most flags.

The idea is to create a simpler, more consistent sets of flags. Any symbolic shapes (e.g. stars, words, etc) are removed. Consistency of shapes is favored over individuality of each flag, for instance, most circles are only one of 2 sizes.

Typing Accents

Fri, 25 Jul 2025 00:00:00 +0000

Typing accents requires a whole lot of processing that seems counter-intuitive at first glance. For a user, “tapping the key é” and “seeing é on the screen” is so common, that one rarely tries to understand what is going on.

I am by no mean an expert in this domain, but I learned a lot and wants to share my understanding.

Note: whenever possible, simplified views of various output is given. Some of the tools used are very verbose.

Keyboard

Tue, 27 May 2025 00:00:00 +0000

This keyboard layout is the latest and smallest iteration in my keyboard journey. I’ve managed to fit everything into 34 keys, while removing anything superfluous.

Letting the classical QWERTY layout go in favor of one that made sense to me really helped shaping a more personal and simple layout.

See the code at https://github.com/nobe4/keyboards/blob/main/ferris/keymap.c

Glossary

[ ]: space key
GUI: “command”, “super”, or “windows”.
OS: OS layer
SY: Symbol layer

Default layer

			q w f p g j l u y '
a r s t d h n e i o
z x c v b k m , . ↵
 ⇑ [ ] CTRL SY
		

`⇑` held: Shift layer

			Q W F P G J L U Y "
A R S T D H N E I O
Z X C V B K M ; : ↵
 ⇑ [ ] CTRL SY
		

Changing the defaults to have more logical shifted characters: '", ,;, .:.

nobe4

Fri, 31 Jan 2025 00:00:00 +0000

What’s a nobe4?

That’s the alias I have used for as long as I could.

I like the tabula rasa reference, that it can mean that I try to live with no preconception and with an open mind.

It’s pronounced:

no before

ˈnoʊ bɪˈfɔr

Stars

Thu, 23 Jan 2025 00:00:00 +0000

Being idealistic is hard for me to brush off. I overly enjoy perfection and the feeling of having created something just right.

Having guidelines, or rules matters only if consistently applied. Code fits greatly to this via linter, type checkers, formatters, etc.

For other things, I find it useful to have guiding principles, less as strong rules and more as unreachable states. Aiming, if never reaching, for something perfectly great.

A*ism

Wed, 11 Dec 2024 00:00:00 +0000

Agnosticism and Atheism are often used interchangeably.

However they mean different things, and ought to be used precisely.

Atheism: absence of belief
- Implicit Atheism absence of belief without conscious rejection
- Explicit Atheism: absence of belief with conscious rejection
- Negative Atheism: absence of belief without assertion of absence
- Positive Atheism: absence of belief with possibility of absence
- Explicit Positive Atheism: absence of belief with assertion of absence
Agnosticism: absence of knowledge

Determinism

Sat, 07 Dec 2024 00:00:00 +0000

If causality has gaps

It means that some effects are not the products of what came before. They emerged outside of the physical laws, in a non-physical space.

Gaps are not unexplainability: electricity was not explained a thousand year ago. Moreover, future research could explain phenomena we don’t yet understand.

Gaps are not unpredictability: the weather is unpredictable because of its complexness, yet it respects known laws of atmospheric dynamics and physics.

Code organization

Tue, 26 Nov 2024 00:00:00 +0000

Here’s a pattern I use to organize all my development work.

~/dev/{owner}/{repo}

This makes understanding where a repository is much easier than having a flat structure.

It becomes easy to switch context using a function like z:

#!/usr/bin/env bash

cd "$(
	fd . "${HOME}/dev" \
		--type d \
		--color never \
		--max-depth 2 \
		| fzf --select-1 --query "${*}"
)" || exit

E.g.

$ z

 /Users/nobe4/dev/nobe4/cli/
 /Users/nobe4/dev/cli/go-gh/
 /Users/nobe4/dev/cli/cli/
▌ /Users/nobe4/dev/cli/
 4/117 ────────────────────
> cli

Using this pattern in mind, I wrote projector.sh.

Lazy Lazy Loading

Sun, 21 Jul 2024 00:00:00 +0000

In this blog post, I showcase how I maintain my cat website.

Past

I used to maintain a piece of code that roughly did the following:

content = "<body>"

for picture in ls("./pictures"):
 content += picture

content += "</body>"

Which generated an HTML file I could then deploy:

<body>
 <img src="pictures/0.jpeg" />
 <img src="pictures/1.jpeg" />
 <img src="pictures/2.jpeg" />
 ...
</body>

That meant that for any new picture, the build script would have to run again. I removed the build step by doing something much worse.

Pure Data Sequencer

Thu, 26 Oct 2017 00:00:00 +0000

In this post I’d like to present a patch I made for Pure Data, namely a sequencer.

Pure What?

Pure Data (Pd) is a visual programming language developed by Miller Puckette in the 1990s for creating interactive computer music and multimedia works. - Wikipedia

Coming from a text-based programming experience, it’s a connect box with lines type of programming game. Although I am relatively new to this technology, I can already tell that it’s a lot of fun to play with!

Cube

Mon, 16 Oct 2017 00:00:00 +0000

This blog post presents the little toy I made while exploring the HTML5’s canvas and a cube’s visualisation with changing perspectives.

You can see the result here: Cube.

Preparing the canvas and brushes

Let start with the canvas wrapper, the non-cube side of the project.

After getting the canvas and its context, we set fixed sizes for various elements of the page:

const canvas = document.getElementById("canvas");
const ctx = canvas.getContext("2d");
const HEIGHT = canvas.height;
const WIDTH = canvas.width;
const pointSize = 10;
var debug = true;
var step = 0;

Next, a few different functions to clear/display stuff on the canvas:

LAMP CTF4

Wed, 20 Sep 2017 00:00:00 +0000

Source: https://www.vulnhub.com/entry/lampsecurity-ctf4,83/

This LAMP challenge is most likely to be focused around casual Linux-Apache-MySQL-PHP vulnerabilities. Let’s check the robots.txt file first:

			User-agent: *
Disallow: /mail/
Disallow: /restricted/
Disallow: /conf/
Disallow: /sql/
Disallow: /admin/
		

/mail/

Looks like a webmail service, we can’t login for now, moving on.

/restricted/

There’s another service here, protected by a .htaccess file login, but we don’t have any access, moving on.

/conf/

This page crashes with a 500 error that gives two interesting pieces of information:

Shellcode for/by a Newbie

Sat, 02 Sep 2017 00:00:00 +0000

I wrote this blog post with a simple goal in mind: I never took the time to understand fully how a shellcode worked. I know about it, I know that it works, but I don’t know how. So I made myself write this in order to finally grasp its logic. Ready? Let’s dig in!

For this article I’m using a Ubuntu Trusty 32bits (with Vagrant).

The wrapper

In order to execute a shellcode, we’re going to use a simple wrapper, written in C. Later in the blog post, I’ll assume that only shellcode changes, so I’ll only reference it.

Vim As An Anti-Keylogger

Thu, 22 Jun 2017 00:00:00 +0000

OK, this is a fictional title made just to sound cool, a more accurate title would be:

How debugging a Vim plugin made me discover a keylogger

Once upon a shell…

Quick note about fugitive. I’m using this Vim plugin a lot, it’s one of the few I couldn’t live without. I highly recommend it!

You can commit, show the status, add, revert, blame, directly from Vim It’s a delight.

/dev/random: Relativity

Sat, 26 Nov 2016 00:00:00 +0000

Writeup by npny and nobe4.

nmap reveals the following open ports: 21,22, 80.

The HTTP does not reveal anything special, static HTML.

On the ports 21 and 22 the default/basic username don’t work.

We can see the FTP on port 21 is an old ftpd version with the mod_sql activated.

From various links we understand that there is a SQL injection on this plugin that allow a user to login without valid credentials.

Using the code on this exploit doesn’t work but changing the -- with # (another comment symbol) works, the payload is:

/dev/random: Pipe

Wed, 19 Oct 2016 00:00:00 +0000

Writeup by npny and nobe4.

Firstly, we run nmap against the website, to discover that (among others), the ports 80 and 22 are open.

SSH doesn’t yield any results, and we try, without luck, a possible exploit against the used version.

HTTP is a lot more interesting:

An HTTP password is asked when trying to access the main page. After a few random try on the different HTTP verbs we try to access the default index.php file, which seems to have the same security. But, making a POST request on the file returned a valid HTML page. Nice!

Golfed Dragon's Curve

Sun, 26 Jun 2016 00:00:00 +0000

Little dragon’s curve.

I got bored on a rainy Sunday and I thought I would try to mix mathematic and JavaScript.

I love fractals and I saw neat golfed examples of what you can do with the canvas (e.g. this 128 bytes dragon’s curve), so I tried to create a simple dragon’s curve generation visualisation.

My attempt displays splittings of the initial segment as it gradually turns into a curve.

Here is the full code. To make it work, you need a fixed-size canvas whose id is a (demo at the end).

Vim Gitignore view

Sun, 06 Mar 2016 00:00:00 +0000

Introduction

One workflow I came across a lot during my programing days is the following:

git status
vi .gitignore
# [Edition ...]
git status
vi .gitignore
# [Edition ...]
git status
git commit

I don’t usually create the best gitignore pattern on the first time, so I need to test multiple times for correctness.

Wait, that seems to be a lot of repetition ! Let’s create a vim plugin !

Vim Syntax Generator

Sat, 10 Oct 2015 00:00:00 +0000

When you feel like knowing all this syntax stuff, perhaps write a blog post ;) - VanLaser

I may not know everything about the syntax mechanisms in Vim, but at least I’ll share what I understood building a syntax file generator.

TL;DR

How I created a syntax file generator for displaying StackExchange API values.

I have some data:

{
 "has_more": true,
 "items": [
 {
 "answer_count": 1,
 "creation_date": 1441047662,
 "is_answered": false,
 "last_activity_date": 1441047900,
 "link": ...

And I define a formatting style:

208 Energy

Tue, 30 Jun 2015 00:00:00 +0000

Scroll all the way down !

For the release of the new Peugeot 208, we developed at Cogit Studio a single scrolling webpage to beautifully present the car.

Feel the energy (website down)

308 Experience

Sun, 22 Mar 2015 00:00:00 +0000

Scroll all the way down !

For the release of the new Peugeot 308, we developed at Cogit Studio a single scrolling webpage to beautifully present the car.

Live the Experience (website down)

The Ad Filter

Sun, 15 Mar 2015 00:00:00 +0000

The Ad Filter is a Chrome and Firefox extension that only shows the “best” ads.

This work was done with Cogit Studio and D&AD.

About

Mon, 01 Jan 0001 00:00:00 +0000

I am nobe4, a french developer, constant learner, and music listener.

I am seeking enlightenment through coding and music making.

CV

Mon, 01 Jan 0001 00:00:00 +0000

Experience

GitHub

2023 Sep - Present
Berlin, DE
Senior Security Engineer

2021 May - 2023 Sep
Berlin, DE
Security Engineer

TBD, still breaking things over there

N26

2019 Sep - 2021 April
Berlin, DE
Security Engineer

2018 May - 2019 Sep
Berlin, DE
Junior Security Engineer

Joined the original security team. Did all things security: education, auditing, pentest, incident response, built and managed a SIEM.

Technologies:

Elasticsearch
Python/Ruby/Bash
Datadog
Saltstack
Docker
Hashicorp/*
AWS

Meetreel

2017 Aug - 2018 Feb
Paris, FR
Co-founder, CTO

N-Back

Mon, 01 Jan 0001 00:00:00 +0000

X-Back Count

Pairs

Mon, 01 Jan 0001 00:00:00 +0000

Value count Letter count

Plants

Mon, 01 Jan 0001 00:00:00 +0000

Terms

Growing season: Spring + Summer

All plants

want lukewarm water
are potentially toxic to pets

TODO

research repotting
research prunning

Privacy policy

Mon, 01 Jan 0001 00:00:00 +0000

This privacy policy covers how data is collected and processed on nobe4.fr.

Data collected

GoatCounter is used to perform analytics without collecting personal information.

It is configured to collect the following information:

Visited page address
Referrer
User-Agent
Screen size
Country and Region
Language

This is processed to understand site usage.

GoatCounter doesn’t use cookies.

See GoatCounter privacy policy.

Disclosure of information

No information is shared with third parties.

~ on nobe4

Nix RPi Bootstrapping

Nix bin alias

Nix-Darwin shell override

Moving aliases to Nix

When ln is not idempotent

Nix ln, the wrong ways

Current configuration

Nix packaging

The plan

Great Flag Unification

Typing Accents

Keyboard

Default layer

⇑ held: Shift layer

nobe4

Stars

A*ism

Determinism

If causality has gaps

Code organization

Lazy Lazy Loading

Past

Pure Data Sequencer

Pure What?

Cube

Preparing the canvas and brushes

LAMP CTF4

/mail/

/restricted/

/conf/

Shellcode for/by a Newbie

The wrapper

Vim As An Anti-Keylogger

How debugging a Vim plugin made me discover a keylogger

/dev/random: Relativity

/dev/random: Pipe

Golfed Dragon's Curve

Vim Gitignore view

Introduction

Vim Syntax Generator

TL;DR

208 Energy

308 Experience

The Ad Filter

About

CV

Experience

GitHub

N26

Meetreel

N-Back

Pairs

Plants

Privacy policy

Data collected

Disclosure of information

`⇑` held: Shift layer