lwillek

Default KexAlgorithms / Ciphers for Debian

--> post-quantum key agreement

See also https://www.openssh.org/pq.html

OpenSSH has offered post-quantum key agreement (KexAlgorithms) by default since release 9.0 (April 2022), initially via the sntrup761x25519-sha512 algorithm. More recently, in OpenSSH 9.9, we have added a second post-quantum key agreement mlkem768x25519-sha256 and it was made the new default scheme in OpenSSH 10.0 (April 2025).

lwillek

Cleaning Up Local Git Branches: A Practical Guide

Imagine you’ve been hopping between tasks for a few months, creating a new branch for every ticket. Many were merged, some were abandoned, and others were just experiments. Now your local repository is overflowing with dozens of branches you no longer need.

This guide helps you clean up, by creating a script which:

• identifies local branches that don’t exist on any remote or whose upstream has been deleted,
• shows you what it plans to delete,

lwillek

Debian 12 → 13 Upgrade, Modernisierung & Bereinigung

Backup

sudo cp -a /etc/apt/sources.list /etc/apt/sources.list.bak
dpkg --get-selections > ~/pakete-backup.txt

Sicherheit beim update:

lwillek

Securely Access Secrets in GitHub Actions

Are you stressed because a coworker left the company without documenting secret usage? Struggling to reverse-engineer encrypted secrets for critical workflows?

Simplify your process with this guide on securely encrypting and decrypting secrets in GitHub Actions. This practical approach ensures your sensitive information remains secure, helps to maintain smooth operations and enhance your security practices.

Learn how to use environment variables and OpenSSL for robust encryption, ensuring you have the tools to handle secrets efficiently. Stay secure and organised with these straightforward steps.

lwillek

Using Finder is the simplest way to find hidden files.

• Press Command + Shift + . (the period key). This will show hidden files in the folder.
• To hide the files again, press Command + Shift + . again.
• You can also click your desktop and press Command + Shift + . to show hidden files on your desktop.

Permanent configuration

Use the Terminal to configure how hidden files are shown.

lwillek

How To Remove Secrets From a GitHub Repository

We often work with sensitive information, such as API keys or passwords. It is essential to maintain the confidentiality of this secrets and prevent unauthorized access.

Despite our best efforts, accidents do occur, resulting in the unintentional exposure of secrets.

Some data from 2023 on it:

• 7 commits out of 1,000 exposed at least one secret.
• 4.6% of active repositories leaked a secret.

lwillek

gocryptfs on MacOS - manual installation

To install gocryptfs, macFUSE is required, which relies on a license not accepted by Homebrew. This is why the upgrade command refuses to work. Installing or updating via homebrew fails for this reason. Here you learn how to manually install and update gocryptfs.

precondition

As precondition, ensure you have Xcode, git and the "Go" programming language installed:

xcode-select --install

lwillek

#cloud-config

package_update: true
package_upgrade: true

groups:
  - docker

system_info:
  default_user:

lwillek

Install Python and virtual environment with help of pyenv

Install OS-specific dependencies

Before you install pyenv itself, you’re going to need some OS-specific dependencies. Pick whatever suits you.

Linux (Debian/Ubuntu)

$ sudo apt-get install -y make build-essential libssl-dev zlib1g-dev \
libbz2-dev libreadline-dev libsqlite3-dev wget curl llvm libncurses5-dev \
libncursesw5-dev xz-utils tk-dev libffi-dev liblzma-dev python-openssl git