Character Encoding

The in-band byte sequences, starting with the escape character, that tell a terminal to move the cursor, change color, or clear the screen, inherited from 1970s video terminals and still how every command-line tool draws.

Turning audio into text, and the reasons real-world accuracy is set by the signal more than by the model.

A way to write arbitrary bytes using 64 safe text characters, so binary data can travel through email, JSON, URLs, and other channels built for text, at the cost of a third more size and with no secrecy at all.

The compression trick that splits text into the tokens a language model reads, by repeatedly merging the most frequent pair of symbols into a new one.

The plain-text table format of rows separated by line breaks and fields separated by commas, universal and simple until quoting, encoding, and spreadsheets get involved.

Picture characters encoded in Unicode, born on Japanese phones in the late 1990s, drawn differently by every platform, and built from sequences of code points that break naive string handling.

The software layer that turns keystrokes into text for writing systems with far more characters than a keyboard has keys, such as Chinese, Japanese and Korean, by letting people type sounds or shapes and choose from candidates.

Domain names written in non-Latin scripts and accented letters, made to work in an ASCII-only DNS by encoding them as xn-- strings, and the browser rules that decide when to show the real characters and when to show the code to block lookalike attacks.

The first stage of reading a program, which groups a stream of characters into tokens such as names, numbers, operators and keywords, usually using regular expressions compiled into a finite automaton, so the parser can work with words rather than letters.

The invisible characters marking where a line of text ends, split three ways since the teletype era between Unix, Windows, and classic Mac OS, and still breaking scripts and diffs.

The short type/subtype label, born in email, that tells a browser how to treat a response, and why browsers that guess when it's missing turned a convenience into a security hole.

The server-side language that began in 1994 as a personal set of homepage tools, spread on cheap shared hosting to run much of the web including WordPress and early Facebook, and survived years of ridicule by getting much faster and stricter.

The everyday string that tells a carrier where to deliver mail, far less regular than forms assume, with postal codes that are delivery routes rather than areas, and a long list of countries and people that don't fit the standard fields.

The interactive command interpreter, and a programming language with unusually sharp edges.

The short, readable, hyphenated part of a URL that names a page, borrowed from newsroom jargon, simple to generate and surprisingly hard to keep stable once other people link to it.

Text messages of up to 160 characters sent between mobile phones, designed in the 1980s as a side feature of the GSM standard and grown into a global habit, a login code channel, and a fraud vector.

An attack in which user input is pasted into a database query and gets run as code, prevented by keeping the query and its data in separate channels.

An interface rendered as text in a terminal, and the design conventions that make command-line tools humane.

Cutting text that doesn't fit and marking the cut with an ellipsis, a layout convenience that hides information, breaks in other languages, and needs care to stay accessible.

Civil time is a political layer over solar time, and its rules change often enough to be data.

The sub-word unit a language model actually reads and writes; the unit of cost and of context.

The address format that names every resource on the web, its parts from scheme to fragment, and why parsing one correctly is harder and more security-relevant than it looks.

Translating a game plus adapting it for a new market, and the drift that adaptation introduces.

A convention placing configuration, data, cache, and state in defined directories rather than the home directory.