davlgd tech blog

The RFC series is almost ten thousand documents that constantly point at each other.

I have spent a year of posts poking at small UNIX commands on three systems: macOS, Debian and Ubuntu.

I mentioned at the end of the net.s3 post that another of my patches in V 0.5.2 deserved its own article.

Every shell script eventually needs somewhere to put something.

I promised this one while writing about expect, where a script ran on my Mac and failed on Linux because of its first line.

V 0.5.2 shipped on July 13th.

Everyone times a command the same way, and almost nobody has run the program they think they are running.

Copying a terminal session into a bug report loses everything: the colours, the order, the pauses, and the half of the output you did not select. script records the session itself, and its companion plays it back at the speed it happened.

An agent that writes code eventually wants to run it, and a container is a thin wall for that.

“Everything is a file” is the line everyone quotes about UNIX and nobody demonstrates. lsof lists open files, and once you see what it counts as a file, the slogan stops being a slogan.

You have a file with no extension, or the wrong one, or one you do not trust.

This blog ran on Astro and the AstroPaper theme from December 2023.

Two jobs that people write scripts for: take a random sample of a file, and cut a big file into smaller ones.

Back in January, Zen C was making the rounds in my feeds: a fresh systems language transpiling to readable GNU C, with V flavour and a few ideas of its own.

sed gets used for jobs that tr does in a quarter of the characters, and usually faster, because tr does not parse a regular expression: it maps bytes.

HTTP has carried a 402 Payment Required status code since RFC 2068 defined HTTP/1.1 in January 1997, reserved for future use and unused ever since.

“Which users are in both lists?”

Every script eventually prints a table, and every one of them prints it badly.

If yes repeats, seq counts.

Your system ships two programs whose entire job is to fail, or to not fail. true exits with status 0, false exits with status 1.