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You have a folder full of files named `invoice_2026_01.pdf`, `invoice_2026_02.pdf`, and a hundred more. You need the ones from the first half of the year, but not the drafts, and definitely not the `i...
You've written a query that pulls every customer in your database. It runs fine. Then someone asks a simple-sounding question: which customers placed an order last month, and what did they spend? Sudd...
You write a few lines of JavaScript to fetch some data, you `console.log` the result, and instead of the object you expected, the console prints `Promise { }`. Nothing is broken, exactly — the code ra...
You've been heads-down on a feature branch for four days. The tests pass, the code is clean, you're proud of it. Then you open the pull request and someone leaves a one-line comment: "Can you rebase o...
It usually starts with a small, forgettable task. You write a script that backs up a folder, or clears out old log files, or emails yourself a summary. It works beautifully — the first time, when you ...
You already know how to write a `GROUP BY`. You can total up sales by month, count users by country, average an order value without breaking a sweat. Then someone asks a question that sounds just as s...
You're staring at a log file with 40,000 lines in it. Somewhere in there is the one request that failed, and you know it has a timestamp, an IP address, and the word `timeout` in it. A colleague leans...
There's a moment almost every developer hits early on. You've been using Git for a few weeks. You can `git add`, `git commit`, and `git push` without looking anything up. Then a teammate says somethin...
You've seen the word everywhere. A tutorial says "just run it in Docker." A job posting lists it next to skills you actually have. A coworker shrugs and says "it works on my machine" — then adds, half...
You have a table of sales, and your boss asks a deceptively simple question: "For each salesperson, show me their monthly total and how that compares to the month before." You know how to get the mont...