Screenshot of explainshell.com – interface of the shell command analysis tool

ExplainShell – Understand Shell Commands, Line by Line

🔗 explainshell.com is a brilliant utility for anyone working with Linux or Unix shell environments. While basic commands like cd or ls are commonly understood, more advanced command-line expressions can quickly become cryptic. That’s where ExplainShell shines – helping you understand exactly what each part of a command does. The interface is refreshingly simple: paste in any shell command (e.g., tar -xzvf archive.tar.gz or find . -type f -exec grep -H 'pattern' {} \;) and the tool immediately dissects it. It maps each argument, flag, and operator to documentation snippets pulled from real man pages. You don’t just get a general explanation — you see which part of the command corresponds to which official description. ...

July 28, 2025 · Cogimator Team
Screenshot of randoma11y.com – a tool for generating high-contrast color pairs

Randoma11y – High-Contrast Accessible Color Pairs

🔗 randoma11y.com is a surprisingly effective minimalist tool designed for web developers, interface designers, and accessibility advocates. Its main purpose is to generate random background/text color pairs that meet the WCAG 2.1 contrast ratio requirements, making them readable for people with visual impairments or low vision. Upon each refresh, the site presents a new color combination, displaying both HEX values, the exact contrast ratio (e.g. 9.41:1), and a ready-made CSS snippet. Visitors can vote on whether the combination is good or bad, slowly building a kind of crowdsourced archive of aesthetically pleasing and functionally accessible color sets. ...

July 28, 2025 · Cogimator Team
Screenshot of the Fourmilab homepage

Fourmilab – John Walker’s online laboratory

Fourmilab is a sprawling digital lab maintained since the 1990s by John Walker, founder of Autodesk and co-author of AutoCAD. It’s one of the web’s oldest personal knowledge hubs — offering simulations, articles, tools, and books that cover astronomy, cryptography, probability, artificial intelligence, spaceflight, and philosophical speculation. Key areas include: – 🔭 real-time astronomical simulators like Your Sky, Earth & Moon Viewer, and orbital calculators – 🔐 tools for encryption, random number generation, and fictional world building – 📚 full e-books including The Hacker’s Diet and The Autodesk File – 🧠 essays on technological singularity, digital autonomy, transhumanism, and future shock ...

July 26, 2025 · Cogimator Team