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Practical guides
Understand how browser tools, passwords and privacy features work, including their limits.
Why SHA-256 hashes differ and how to verify a fileTwo SHA-256 hashes do not match? Check the file, encoding and line endings, then compare the result with a trusted reference using a simple example.Clean a list without changing its valuesRemove empty lines and duplicates carefully. Preserve meaningful spaces, letter case and leading zeroes, then choose the right sort order.Convert pixels to rem with the correct root font sizeConvert CSS pixels to rem using the actual root font size. Check the calculation, six-decimal rounding and the layout after zooming.Compare CSV exports by identifier, without mistaking a sort for a changeUse a fictional inventory to compare two CSV exports by a composite key. Reproduce exact row and cell differences, diagnose duplicate keys and save a local report.Redact a support screenshot without hiding the useful contextPractise opaque screenshot redaction on three fictional values, check exact pixel coordinates, and inspect a flattened PNG before sharing.Convert a Windows-1252 file to UTF-8 without changing its line endingsA byte-by-byte example for preserving accents, the euro sign and CRLF when converting a local text file to UTF-8.From semicolon CSV to JSON, keeping leading zeroesWork through a fictional CSV with quotes and a multiline cell: change its delimiter, inspect records, and convert to JSON while keeping string values.Prepare an image for sharing: metadata and compressionInspect supported EXIF fields, create a cleaned copy, check it and compress your image. Understand formats, limitations and final sharing checks.Read a QR Code from a Screenshot Without Opening the LinkDecode a QR screenshot locally in your browser. Inspect its text before opening a link, with a worked example, practical steps and clear limits.Local-first softwareLocal-first software keeps data and core functionality on a user’s device, syncing with other devices only when needed.Local vs cloud toolsLocal tools process information on your device. Cloud tools send it to remote servers, which can be useful but introduces additional data handling.Password entropy explainedPassword entropy estimates how difficult a secret is to guess, measured in bits. It depends on the size of the possible character set and the number of random choices.How passwords are crackedAttackers may guess common passwords, reuse leaked credentials, or test candidate combinations offline against stolen password hashes.Browser privacy basicsYour browser can process many tasks locally. Check permissions, storage, extensions, and network requests to understand what a page can access.