herrbischoff/cheatsheets

30 seconds of code (Chalarangelo/30-seconds-of-code) is a GitHub repository that points to a collection of coding articles at 30secondsofcode.org, maintained by Angelos Chalaris. Each article pairs a code snippet with an explanation and an example, and the snippets themselves are licensed CC-BY-4.0; the project isn't taking new content submissions right now, per its README.

trimstray/the-book-of-secret-knowledge is a highly-starred GitHub repository offering a curated collection of resources for system and network administrators, DevOps, pentesters, and security researchers, though it aims to be useful for everyone. It compiles inspiring lists, manuals, cheatsheets, blogs, hacks, one-liners, and CLI/web tools, organized into main chapters such as CLI Tools, GUI Tools, Systems/Services, Networks, Hacking/Penetration Testing, and Shell One-liners. The project emphasizes quality over quantity, welcoming contributions that are inviting, clear, not tiring, and useful, with an active RSS feed for updates.

GitHub gitignore templates is the collection maintained in the github/gitignore repository, licensed CC0-1.0. GitHub uses this exact list to fill the .gitignore chooser shown when you create a new repository or file, and it splits templates into a curated root set for common languages, a Global folder for editors and operating systems, and a community folder for narrower or version-specific cases.

DevOps Exercises is a GitHub repository collecting 2624 questions and exercises spanning Linux, networking, Kubernetes, Terraform, and cloud platforms, written as plain markdown Q&A with no app or course wrapped around it.