murkshelf

JSON Formatter

Sun, 25 Oct 2026 00:00:00 +0000

Paste JSON, press a button. Everything happens locally in this page — no requests, no storage.

SQL: window functions in five examples

Sun, 11 Oct 2026 00:00:00 +0000

Window functions feel like a dialect of SQL you learn in a parallel universe, but they come down to one idea: aggregate without collapsing rows. A GROUP BY squashes the table; a window function keeps every row and adds the aggregate beside it.

All examples below work in PostgreSQL; most are identical elsewhere.

1. A total next to every row

SELECT
 employee,
 department,
 salary,
 SUM(salary) OVER () AS payroll_total
FROM salaries;

Every row survives, and each carries the same grand total.

Docker: the cleanup commands I always forget

Thu, 03 Sep 2026 00:00:00 +0000

Every few weeks Docker eats 30 GB and I can’t remember the exact flags. Writing them down once and for all.

Look before you delete

docker system df # how much Docker is actually using
docker ps -a # containers, including stopped ones
docker images -a # images, including intermediate layers
docker volume ls # volumes

docker system df -v gives the per-item breakdown when you need to know exactly what is eating the space.

Git: rebase vs merge — a practical rule of thumb

Fri, 14 Aug 2026 00:00:00 +0000

Every team argues about this. The rule that ends the argument:

Rebase commits that only you have seen. Merge commits that anyone else has already seen.

Rebase rewrites history — it takes your commits and replays them on top of a new base, creating new commits with new hashes. If a hash you rewrote exists on someone else’s machine, you now have two divergent histories and a bad afternoon. If nobody ever pulled those hashes, rewriting them costs nothing.

tmux: the five commands that cover 95% of usage

Mon, 20 Jul 2026 00:00:00 +0000

I resisted tmux for years because every cheat sheet starts with forty key bindings. In practice five cover almost everything:

tmux new -s work # start a named session
Ctrl-b d # detach (everything keeps running)
tmux attach -t work # come back later
Ctrl-b % # split left/right
Ctrl-b " # split top/bottom

Everything else is bonus. The point of those five: your session survives a dropped SSH connection, a closed terminal window, or a laptop sleep. Start the session on the machine where the work runs, detach, reattach from anywhere.