Obsidian
Obsidian is a local-first Markdown note-taking and knowledge-management application. Instead of locking your information into a proprietary database, it stores your notes as ordinary .md Markdown files on your computer.
For a technical user, it can be much more than a note-taking program. You can use it as a personal technical wiki for Linux/Gentoo commands, C++ notes, installation procedures, troubleshooting logs, AI/LLM experiments, code snippets, project documentation, and research.
A useful vault structure would be:
One of Obsidian's strongest features is linking notes:
Those links create a navigable personal knowledge base, and Graph View can visualize the relationships between your notes. Obsidian also supports thousands of plugins; examples highlighted by Obsidian include Calendar, Kanban, Dataview, Outliner, and Tasks.
Your notes remain local and work offline. Sync is optional, and Obsidian's official Sync service provides end-to-end encryption, version history, collaboration, and selective synchronization. The base application is free; Sync and Publish are optional paid services.
Given your Gentoo environment, Obsidian could work especially well as a permanent Gentoo/Linux engineering knowledge base instead of having commands and solutions scattered across terminal history and conversations. For example, every time you solve a Portage, Intel Arc, Ollama, OBS, or systemd problem, you could preserve the final working solution as a searchable Markdown note.