Category: Tooling

What is jq? A fast command-line JSON processor for filtering, transforming, and querying JSON in shell pipelines. Learn syntax, filters, and pitfalls.

What is grep? Learn how the command-line search tool finds text with patterns, key flags, recursive search, regex modes, pipes, and common pitfalls.

What is a git stash? Learn how to shelve uncommitted changes, pop and apply them, stash untracked files, manage the stash stack, and avoid pitfalls.

What is a git rebase? Learn how rebasing replays commits for a linear history, rebase vs merge, interactive rebase, the golden rule, and how to recover.

What is a regex character class? Learn bracket sets, ranges, negation, shorthand like d and w, POSIX classes, and common pitfalls with clear examples.

How QR codes encode data, what error correction and the quiet zone do, which versions and modes exist, and how to make one that scans reliably.

The curl flags worth memorising: methods, headers, bodies, auth, following redirects, saving output, and debugging with a verbose trace.

When to use a 301 versus a 302, how caching and SEO differ, where 307 and 308 fit, and why the method-preserving codes exist.

Apache RewriteRule and Redirect versus nginx rewrite and return: 301 vs 302, regex backrefs, flags, and testing before you deploy.

How a curl command maps to fetch, axios, requests and Go, plus the quiet pitfalls: implicit POST, content-type, and shell quoting.