Collection

Link collection

This is a growing collection of references, useful finds and notes that have proved worthwhile over time. Some are clearly technical, others simply practical.

Not everything is new, and not every link matters equally to everyone. But some resources remain useful for years.

Personal profiles

GitHub – code, repositories and technical traces.
XING – professional profile and context.
LinkedIn – networking and outward-facing profile.

Software & web development

SELFHTML – long-standing German reference for HTML and CSS.
MDN Web Docs – reliable documentation for modern web work.
Tailwind CSS – utility-first CSS documentation.
DaisyUI – component ideas on top of Tailwind.

Linux & administration

Linux Kernel Archives – the official source around the kernel.
man7 – excellent Linux man pages on the web.
Linuxize – practical Linux tutorials.
Proxmox documentation – virtualisation and operations.

Data & databases

PostgreSQL docs – official documentation with real depth.
MySQL docs – reference material and practical details.
Oracle Database – entry point into Oracle topics.
pgAdmin – a common PostgreSQL administration tool.

Security

Wazuh – open-source security monitoring.
Lynis – audits and hardening approaches for Linux systems.
OWASP – web security guidance and best practices.

Training & learning

LinkedIn Learning – structured courses for many IT topics.
Udemy – broad course selection with mixed quality.
Oracle LiveLabs – practical Oracle exercises and environments.
Linux Foundation Training – Linux and open source from the source.