Guides & How-to Articles

Practical walk-throughs that explain the how and why behind the tools, with examples you can copy.

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Learn how to create a strong password you can actually remember: entropy in plain terms, the passphrase method with real

Learn the five cron fields, the special characters *, /, -, L, W and #, and copy ready-made schedules for common jobs. I

Compare JSON and YAML for configuration and data: syntax, comments, types and tooling. Learn when to use each and conver

Step-by-step guide to reading a QR code from an image, plus tips for blurry or angled codes and an explanation of the QR

A quick reference for Markdown: headings, emphasis, lists, links, images, code, tables and task lists. Preview your Mark

Master percentage math with three formulas: X% of Y, what percent one number is of another, and percent change. Discount

Compound interest explained with real numbers: the formula, a compounding-frequency comparison, the Rule of 72, and a wo

Use the 28/36 rule to find how much house you can afford. Worked $90k example, PITI breakdown, price table, and a free m

Understand how a mortgage payment splits into principal and interest, how to read an amortization schedule, and how extr

Calculate concrete for any slab: the length × width × depth formula, cubic-yard conversion, waste factor, and bag math —

Work out how many litres of paint a room needs: measure the walls, subtract doors and windows, allow for coats and waste