My name is Ian Fisher. I'm a software developer in New York City. In the wider world, I'm best known for creating CityQuiz.io, a geography quiz website. I write online about software, language, and literature.
As of fall 2025, I am currently teaching CS644: Intro to Systems Programming.
If you'd like to get in touch, send an email to my first name @ the name of this website.
Recent posts
- Notes on Wikipedia after 10,000 edits (Sep 2025) – Reflections on the world's largest free encyclopedia after a milestone in my editing career.
- Robustly parsing flags in Bash scripts (Aug 2025) – A surprisingly pleasant library for parsing command-line flags in Bash shell scripts.
- One month of LLMs (Aug 2025) – A collection of my writings on large language models, including "A mental model of LLMs", "My LLM tooling", "My personal LLM evals", "Can an LLM write literary prose?", "LLMs outside of programming", and "CSS recipes from Claude Code".
- A Vale plugin for proofreading English prose (May 2025) – garner-vale is a collection of stylistic suggestions and corrections for English prose, written as a plugin for the command-line tool Vale. It has over 200 distinct rules covering more than 3,000 words and phrases.
- Fast concordances in Go (Apr 2025) – fast-concordance is a Go program that creates instant concordances from a corpus of over 1,200 classic books, courtesy of Standard Ebooks.
Favorites
- What file permissions does mv need? (Nov 2024) – An explanation of the Unix file permissions that are required to run the 'mv' command.
- Khaganate: a suite of personal productivity software (Feb 2022) – A description of my personal productivity system.
- A subtle garbage collector bug (Jul 2020) – My most memorable bug: a memory error in a hand-written mark-and-sweep garbage collector.
- Type-safe generic data structures in C (Jun 2020) – Techniques for writing generic data structures in C using pointer casts and code generation through macros.
- Writing an interpreter and debugger for an assembly language (May 2020) – The design and implementation of a toolkit for a pedagogical assembly language that included an interpreter, debugger and assembler and disassembler.