Today I Learned

My Today I Learned snippets. Inspired by jbranchaud/til, which I spotted on Hacker News.

Search these TILs at https://til.simonwillison.net/

583 TILs so far. Atom feed here.

github-actions

• Only run GitHub Action on push to master / main - 2020-04-19
• Dump out all GitHub Actions context - 2020-04-19
• Set environment variables for all steps in a GitHub Action - 2020-04-19
• Commit a file if it changed - 2020-04-19
• Running different steps on a schedule - 2020-04-20
• Updating a Markdown table of contents with a GitHub Action - 2020-07-22
• Using grep to write tests in CI - 2020-08-19
• Skipping a GitHub Actions step without failing - 2020-08-22
• Open a debugging shell in GitHub Actions with tmate - 2020-09-14
• Talking to a PostgreSQL service container from inside a Docker container - 2020-09-18
• Using Prettier to check JavaScript code style in GitHub Actions - 2020-12-31
• Running tests against PostgreSQL in a service container - 2021-02-23
• Installing different PostgreSQL server versions in GitHub Actions - 2021-07-05
• Attaching a generated file to a GitHub release using Actions - 2021-09-07
• Storing files in an S3 bucket between GitHub Actions runs - 2021-12-07
• Testing against Python 3.11 preview using GitHub Actions - 2022-02-02
• Using the GitHub Actions cache with npx and no package.json - 2022-03-22
• Deploying a live Datasette demo when the tests pass - 2022-03-27
• GitHub Actions job summaries - 2022-05-17
• Optimizing PNGs in GitHub Actions using Oxipng - 2022-05-18
• Conditionally running a second job in a GitHub Actions workflow - 2022-07-11
• Ensure labels exist in a GitHub repository - 2022-09-25
• actions/setup-python caching for setup.py projects - 2022-11-28
• Running tests against multiple versions of a Python dependency in GitHub Actions - 2023-09-15
• Serving a JavaScript project built using Vite from GitHub Pages - 2023-10-23
• GitHub Actions, Issues and Pages to build a daily planner - 2024-01-01
• Creating GitHub repository labels with an Actions workflow - 2024-02-09
• Running cog automatically against GitHub pull requests - 2024-11-06
• Building and deploying a custom site using GitHub Actions and GitHub Pages - 2025-03-18
• Using uvx in GitHub Actions in a cache-friendly way - 2026-07-13

python

• Convert a datetime object to UTC without using pytz - 2020-04-19
• macOS Catalina sort-of includes Python 3 - 2020-04-21
• Generated a summary of nested JSON data - 2020-04-28
• Installing and upgrading Datasette plugins with pipx - 2020-05-04
• Use setup.py to install platform-specific dependencies - 2020-05-05
• Build the official Python documentation locally - 2020-05-08
• Introspecting Python function parameters - 2020-05-27
• Password hashing in Python with pbkdf2 - 2020-07-13
• How to call pip programatically from Python - 2020-08-11
• Outputting JSON with reduced floating point precision - 2020-08-21
• Debugging a Click application using pdb - 2020-09-03
• Understanding option names in Click - 2020-09-22
• Explicit file encodings using click.File - 2020-10-16
• Decorators with optional arguments - 2020-10-28
• Running Python code in a subprocess with a time limit - 2020-12-06
• Controlling the style of dumped YAML using PyYAML - 2020-12-07
• Relinquishing control in Python asyncio - 2020-12-29
• Packaging a Python app as a standalone binary with PyInstaller - 2021-01-04
• Handling CSV files with wide columns in Python - 2021-02-15
• Using io.BufferedReader to peek against a non-peekable stream - 2021-02-15
• Tracing every executed Python statement - 2021-03-21
• Check spelling using codespell - 2021-08-03
• Find local variables in the traceback for an exception - 2021-08-09
• Using Fabric with an SSH public key - 2021-10-06
• Using the sqlite3 Python module in Pyodide - Python WebAssembly - 2021-10-18
• Planning parallel downloads with TopologicalSorter - 2021-11-16
• Using cog to update --help in a Markdown README file - 2021-11-18
• Ignoring a line in both flake8 and mypy - 2021-11-30
• init_subclass - 2021-12-03
• Using C_INCLUDE_PATH to install Python packages - 2021-12-09
• Safely outputting JSON - 2021-12-17
• Annotated explanation of David Beazley's dataklasses - 2021-12-19
• Streaming indented output of a JSON array - 2022-01-17
• Generating a calendar week grid with the Python Calendar module - 2022-03-31
• Efficiently copying a file - 2022-05-13
• Freezing requirements with pip-tools - 2022-07-14
• struct endianness in Python - 2022-07-28
• Defining setup.py dependencies using a URL - 2022-08-13
• Running PyPy on macOS using Homebrew - 2022-09-14
• Using psutil to investigate "Too many open files" - 2022-10-13
• Simple load testing with Locust - 2022-10-22
• os.remove() on Windows fails if the file is already open - 2022-10-25
• The pdb interact command - 2022-10-31
• Upgrading a pipx application to an alpha version - 2023-01-11
• Installing lxml for Python on an M1/M2 Mac - 2023-01-27
• Calculating embeddings with gtr-t5-large in Python - 2023-01-31
• A few notes on Rye - 2023-04-26
• The location of the pip cache directory - 2023-04-28
• TOML in Python - 2023-06-26
• CLI tools hidden in the Python standard library - 2023-06-28
• Python packages with pyproject.toml and nothing else - 2023-07-07
• Quickly testing code in a different Python version using pyenv - 2023-07-10
• Using tree-sitter with Python - 2023-07-13
• Protocols in Python - 2023-07-26
• Checking if something is callable or async callable in Python - 2023-08-04
• A simple pattern for inlining binary content in a Python script - 2023-08-19
• Using pprint() to print dictionaries while preserving their key order - 2024-01-14
• Getting Python MD5 to work with FIPS systems - 2024-02-13
• Programmatically comparing Python version strings - 2024-03-17
• Trying out free-threaded Python on macOS - 2024-07-12
• Using uv to develop Python command-line applications - 2024-10-23
• Installing flash-attn without compiling it - 2024-10-24
• Fixes for datetime UTC warnings in Python - 2024-12-12
• Geocoding from Python on macOS using pyobjc-framework-CoreLocation - 2025-01-26
• Trying out Python packages with ipython and uvx - 2025-02-13
• Testing different Python versions with uv with-editable and uv-test - 2025-10-08

zeit-now

• Running a Python ASGI app on Vercel - 2020-04-19
• Redirecting all paths on a Vercel instance - 2021-03-27

sqlite

• Lag window function in SQLite - 2020-04-19
• Null case comparisons in SQLite - 2020-04-21
• Compile a new sqlite3 binary on Ubuntu - 2020-04-30
• List all columns in a SQLite database - 2020-05-06
• Using LD_PRELOAD to run any version of SQLite with Python - 2020-06-17
• SQLite BLOB literals - 2020-07-29
• Enabling WAL mode for SQLite database files - 2020-08-09
• Compiling the SQLite spellfix.c module on macOS - 2020-09-19
• Figuring out if a text value in SQLite is a valid integer or float - 2020-09-27
• Replicating SQLite with rqlite - 2020-12-28
• Identifying column combination patterns in a SQLite table - 2021-01-12
• Fixing broken text encodings with sqlite-transform and ftfy - 2021-01-18
• Splitting on commas in SQLite - 2021-02-01
• Querying for items stored in UTC that were created on a Thursday in PST - 2021-03-12
• Using pysqlite3 on macOS - 2021-07-10
• Importing CSV data into SQLite with .import - 2021-07-13
• SQLite aggregate filter clauses - 2021-08-04
• Building a specific version of SQLite with pysqlite on macOS/Linux - 2021-08-14
• Track timestamped changes to a SQLite table using triggers - 2021-08-19
• json_extract() path syntax in SQLite - 2022-01-18
• Ordered group_concat() in SQLite - 2022-02-06
• Combining substr and instr to extract text - 2022-02-15
• The simplest recursive CTE - 2022-03-20
• Counting SQLite virtual machine operations - 2022-03-20
• One-liner for running queries against CSV files with SQLite - 2022-06-20
• Related content with SQLite FTS and a Datasette template function - 2022-07-31
• Trying out SQLite extensions on macOS - 2022-08-03
• Sort by number of JSON intersections - 2022-08-17
• Seeing which functions are unique to a specific SQLite / Datasette instance - 2022-08-23
• SQLite VACUUM: database or disk is full - 2022-08-29
• Returning related rows in a single SQL query using JSON - 2022-09-16
• Finding the SQLite version used by Web SQL in Chrome - 2022-10-28
• SQLite can use more than one index for a query - 2022-12-11
• Comparing database rows before and after with SQLite JSON functions - 2022-12-14
• Geopoly in SQLite - 2023-01-04
• Loading SQLite extensions in Python on macOS - 2023-01-07
• SQLite pragma_function_list() - 2023-01-27
• Combining CTEs and VALUES in SQLite - 2023-01-29
• The SQLite now argument is stable within the same query - 2023-02-05
• Subqueries in select expressions in SQLite - also window functions - 2023-02-08
• Copy tables between SQLite databases - 2023-04-03
• Saving an in-memory SQLite database to a file in Python - 2023-04-08
• Unix timestamp in milliseconds in SQLite - 2023-04-08
• Comparing two training datasets using sqlite-utils - 2023-05-23
• A one-liner to output details of the current Python's SQLite - 2023-08-19
• Calculating the size of a SQLite database file using SQL - 2023-08-21
• Compile and run a new SQLite version with the existing sqlite3 Python library on macOS - 2023-08-22
• Trying out cr-sqlite on macOS - 2023-09-12
• Geospatial SQL queries in SQLite using TG, sqlite-tg and datasette-sqlite-tg - 2023-09-25
• Running Steampipe extensions in sqlite-utils and Datasette - 2023-12-20
• Tracking SQLite table history using a JSON audit log - 2024-02-26
• SQLite timestamps with floating point seconds - 2024-03-13
• Using sqlite-vec with embeddings in sqlite-utils and Datasette - 2024-08-11
• Compiling and running sqlite3-rsync - 2024-10-04
• SQLite triggers - 2025-05-09

presenting

• Using macOS stickies to display a workshop link on the screen - 2020-04-20

macos

• Running pip install -e .[test] in zsh on macOS Catalina - 2020-04-21
• Get Skitch working on Catalina - 2020-04-21
• Close terminal window on Ctrl+D for macOS - 2020-04-21
• Fixing "compinit: insecure directories" error - 2020-04-26
• Finding the largest SQLite files on a Mac - 2020-08-19
• Shrinking PNG files with pngquant and oxipng - 2021-02-07
• Running Docker on an M1 Mac - 2021-05-25
• Using lsof on macOS - 2021-12-11
• Installing Python on macOS with the official Python installer - 2022-02-28
• Trick Apple Photos into letting you access your video files - 2022-04-12
• Seeing files opened by a process using opensnoop - 2022-04-26
• Atuin for zsh shell history in SQLite - 2022-04-26
• Driving an external display from a Mac laptop - 2022-09-10
• Browse files (including SQLite databases) on your iPhone with ifuse - 2022-09-13
• sips: Scriptable image processing system - 2023-02-18
• Using fs_usage to see what files a process is using - 2023-06-15
• Syncing slide images and audio in iMovie - 2023-06-15
• Local wildcard DNS on macOS with dnsmasq - 2023-06-30
• Downloading partial YouTube videos with ffmpeg - 2023-08-26
• Grabbing a transcript of a short snippet of a YouTube video with MacWhisper - 2023-11-30
• Editing an iPhone home screen using macOS - 2023-12-11
• impaste: pasting images to piped commands on macOS - 2024-04-04
• A script to capture frames from a QuickTime video - 2024-04-16
• Transcribing MP3s with whisper-cpp on macOS - 2024-04-26
• Accessing 1Password items from the terminal - 2024-07-09
• Converting ORF raw files to JPEG on macOS - 2025-06-26

cloudrun

• Use labels on Cloud Run services for a billing breakdown - 2020-04-21
• How to deploy a folder with a Dockerfile to Cloud Run - 2020-08-04
• Using the gcloud run services list command - 2020-09-01
• Listing files uploaded to Cloud Build - 2021-04-14
• Switching between gcloud accounts - 2021-05-18
• Increasing the time limit for a Google Cloud Scheduler task - 2021-07-08
• Tailing Google Cloud Run request logs and importing them into SQLite - 2021-08-09
• Using build-arg variables with Cloud Run deployments - 2021-11-19

tailscale

• Restricting SSH connections to devices within a Tailscale network - 2020-04-23
• Using a Tailscale exit node with GitHub Actions - 2025-02-22

pytest

• Session-scoped temporary directories in pytest - 2020-04-26
• How to mock httpx using pytest-mock - 2020-04-29
• Asserting a dictionary is a subset of another dictionary - 2020-05-28
• Registering temporary pluggy plugins inside tests - 2020-07-21
• Code coverage using pytest and codecov.io - 2020-08-15
• Start a server in a subprocess during a pytest session - 2020-08-31
• Using VCR and pytest with pytest-recording - 2021-11-02
• Quick and dirty mock testing with mock_calls - 2021-11-02
• Writing pytest tests against tools written with argparse - 2022-01-08
• Testing a Click app with streaming input - 2022-01-09
• Opt-in integration tests with pytest --integration - 2022-01-26
• pytest coverage with context - 2022-03-04
• Async fixtures with pytest-asyncio - 2022-03-19
• Treating warnings as errors in pytest - 2022-04-01
• Using pytest and Playwright to test a JavaScript web application - 2022-07-24
• Mocking a Textract LimitExceededException with boto - 2022-08-07
• Show files opened by pytest tests - 2022-12-11
• Mocking subprocess with pytest-subprocess - 2023-03-08
• Snapshot testing with Syrupy - 2023-09-26
• Mocking Stripe signature checks in a pytest fixture - 2024-07-01
• Using namedtuple for pytest parameterized tests - 2024-08-31
• Running pytest against a specific Python version with uv run - 2025-02-04
• A tip for debugging pytest-httpx - 2025-05-28
• Subtests in pytest 9.0.0+ - 2025-12-04

github

• Accessing repository dependencies in the GitHub GraphQL API - 2020-04-30
• Paginating through the GitHub GraphQL API with Python - 2020-07-09
• Searching for repositories by topic using the GitHub GraphQL API - 2020-10-09
• Bulk fetching repository details with the GitHub GraphQL API - 2021-01-17
• Syntax highlighting Python console examples with GFM - 2021-01-18
• Transferring a GitHub issue from a private to a public repository - 2021-12-22
• Configuring Dependabot for a Python project - 2022-01-14
• Setting up a custom subdomain for a GitHub Pages site - 2022-05-04
• Reporting bugs in GitHub to GitHub - 2022-07-07
• Migrating a GitHub wiki from one repository to another - 2022-07-28
• Clone, edit and push files that live in a Gist - 2022-09-08
• GitHub Pages: The Missing Manual - 2022-10-31
• Finding uses of an API with the new GitHub Code Search - 2022-12-08
• Bulk editing status in GitHub Projects - 2023-06-29
• Running a Django and PostgreSQL development environment in GitHub Codespaces - 2023-08-10
• Assistance with release notes using GitHub Issues - 2024-08-05
• Publishing a Docker container for Microsoft Edit to the GitHub Container Registry - 2025-06-21
• Configuring GitHub Codespaces using devcontainers - 2025-08-12
• Downloading archived Git repositories from archive.softwareheritage.org - 2025-12-30

node

• Constant-time comparison of strings in Node - 2020-05-01

firefox

• Search across all loaded resources in Firefox - 2020-05-05

markdown

• Converting HTML and rich-text to Markdown - 2020-05-09
• Rendering Markdown with the GitHub Markdown API - 2020-08-22
• Useful Markdown extensions in Python - 2021-04-03

pypi

• Adding project links to PyPI - 2020-05-11
• Publish releases to PyPI from GitHub Actions without a password or token - 2024-01-14

asgi

• Writing tests for the ASGI lifespan protocol with HTTPX - 2020-06-29

heroku

• Using heroku pg:pull to restore a backup to a macOS laptop - 2020-07-10
• Upgrading a Heroku PostgreSQL database with pg:copy - 2020-07-20
• Programatically accessing Heroku PostgreSQL from GitHub Actions - 2020-08-18

javascript

• Implementing a "copy to clipboard" button - 2020-07-23
• Working around the size limit for nodeValue in the DOM - 2020-08-21
• Dynamically loading multiple assets with a callback - 2020-08-21
• Minifying JavaScript with npx uglify-js - 2020-08-30
• Manipulating query strings with URLSearchParams - 2020-10-04
• Writing JavaScript that responds to media queries - 2020-10-21
• Dropdown menu with details summary - 2020-10-31
• Using Jest without a package.json - 2020-12-30
• Scroll page to form if there are errors - 2021-05-08
• Preventing double form submissions with JavaScript - 2021-07-08
• Loading lit from Skypack - 2021-09-21
• Using Tesseract.js to OCR every image on a page - 2021-11-09
• JavaScript date objects - 2022-01-16
• Creating a tiled zoomable image with OpenSeadragon and vips - 2022-08-12
• Copy rich text to the clipboard - 2023-03-10
• Using packages from JSR with esbuild - 2024-03-02

django

• PostgreSQL full-text search in the Django Admin - 2020-07-25
• Adding extra read-only information to a Django admin change page - 2021-02-25
• Writing tests for the Django admin with pytest-django - 2021-03-02
• Show the timezone for datetimes in the Django admin - 2021-03-02
• Pretty-printing all read-only JSON in the Django admin - 2021-03-07
• How to almost get facet counts in the Django admin - 2021-03-11
• Efficient bulk deletions in Django - 2021-04-09
• Enabling the fuzzystrmatch extension in PostgreSQL with a Django migration - 2021-04-18
• Usable horizontal scrollbars in the Django admin for mouse users - 2021-04-20
• Filter by comma-separated values in the Django admin - 2021-04-21
• Django Admin action for exporting selected rows as CSV - 2021-04-25
• migrations.RunSQL.noop for reversible SQL migrations - 2021-05-02
• Enabling a gin index for faster LIKE queries - 2021-05-16
• Django data migration using a PostgreSQL CTE - 2021-05-17
• Using just with Django - 2022-06-06
• Adding a Datasette ASGI app to Django - 2022-10-20
• Building a blog in Django - 2023-08-15
• Using pytest-django with a reusable Django application - 2024-08-07
• Building an automatically updating live blog in Django - 2024-10-02

docker

• Attaching a bash shell to a running Docker container - 2020-08-10
• Running gdb against a Python process in a running Docker container - 2021-03-21
• Installing packages from Debian unstable in a Docker image based on stable - 2021-03-22
• Docker Compose for Django development - 2021-05-24
• Allowing a container in Docker Desktop for Mac to talk to a PostgreSQL server on the host machine - 2022-03-31
• Testing things in Fedora using Docker - 2022-07-27
• Emulating a big-endian s390x with QEMU - 2022-07-29
• Run pytest against a specific Python version using Docker - 2022-09-05
• Using pipenv and Docker - 2022-11-28

homebrew

• Packaging a Python CLI tool for Homebrew - 2020-08-11
• Browsing your local git checkout of homebrew-core - 2020-08-27
• Upgrading Python Homebrew packages using pip - 2020-10-14
• Running a MySQL server using Homebrew - 2021-06-11
• Running the latest SQLite in Datasette using Homebrew - 2022-02-28
• Automatically maintaining Homebrew formulas using GitHub Actions - 2023-06-21
• Upgrading Homebrew and avoiding the failed to verify attestation error - 2024-10-09

zsh

• Customizing my zsh prompt - 2020-08-12
• Passing command arguments using heredoc syntax - 2022-07-07

readthedocs

• Pointing a custom subdomain at Read the Docs - 2020-08-14
• Read the Docs Search API - 2020-08-16
• Using custom Sphinx templates on Read the Docs - 2020-12-07
• Promoting the stable version of the documentation using rel=canonical - 2022-01-20
• Linking from /latest/ to /stable/ on Read The Docs - 2022-01-20
• Updating stable docs in ReadTheDocs without pushing a release - 2023-08-20
• Running pip install '.[docs]' on ReadTheDocs - 2023-11-24

ics

• Providing a "subscribe in Google Calendar" link for an ics feed - 2020-08-21

svg

• Creating a dynamic line chart with SVG - 2020-08-22

linux

• Piping echo to a file owned by root using sudo and tee - 2020-08-24
• Basic strace to see what a process is doing - 2020-09-07
• Enabling a user to execute a specific command as root without a password - 2022-02-13
• Using iconv to convert the text encoding of a file - 2022-06-14

jq

• Converting Airtable JSON for use with sqlite-utils using jq - 2020-08-28
• Loading radio.garden into SQLite using jq - 2021-02-17
• Flattening nested JSON objects with jq - 2021-03-11
• Converting no-decimal-point latitudes and longitudes using jq - 2021-03-11
• Turning an array of arrays into objects with jq - 2021-05-25
• Extracting objects recursively with jq - 2021-07-24
• Convert git log output to JSON using jq - 2023-03-25
• Combined release notes from GitHub with jq and paginate-json - 2023-08-12

bash

• Looping over comma-separated values in Bash - 2020-09-01
• Escaping strings in Bash using !:q - 2020-10-01
• Escaping a SQL query to use with curl and Datasette - 2020-12-08
• Skipping CSV rows with odd numbers of quotes using ripgrep - 2020-12-11
• Finding CSV files that start with a BOM using ripgrep - 2021-05-28
• nullglob in bash - 2022-02-14
• Using awk to add a prefix - 2022-04-08
• Ignoring errors in a section of a Bash script - 2022-06-27
• Start, test, then stop a localhost web server in a Bash script - 2022-12-17
• Running multiple servers in a single Bash script - 2023-08-16
• A shell script for running Go one-liners - 2023-08-20

typescript

• Very basic tsc usage - 2020-09-06

aws

• Display EC2 instance costs per month - 2020-09-06
• Recovering data from AWS Lightsail using EC2 - 2021-01-16
• Adding a CORS policy to an S3 bucket - 2022-01-04
• Helper function for pagination using AWS boto3 - 2022-01-19
• Running OCR against a PDF file with AWS Textract - 2022-06-28
• Using boto3 from the command line - 2022-08-02
• Athena error: The specified key does not exist - 2022-09-27
• Querying newline-delimited JSON logs using AWS Athena - 2022-10-06
• Using S3 triggers to maintain a list of files in DynamoDB - 2025-02-19

jinja

• Turning on Jinja autoescaping when using Template() directly - 2020-09-18
• Formatting thousands in Jinja - 2022-06-08
• Custom Jinja template tags with attributes - 2023-07-01

selenium

• Installing Selenium for Python on macOS with ChromeDriver - 2020-10-02
• Using async/await in JavaScript in Selenium - 2020-10-02

digitalocean

• Running Datasette on DigitalOcean App Platform - 2020-10-06

datasette

• Redirects for Datasette - 2020-11-25
• Serving MBTiles with datasette-media - 2021-02-03
• Querying for GitHub issues open for less than 60 seconds - 2021-03-12
• Running Datasette on Replit - 2021-05-02
• Searching all columns of a table in Datasette - 2021-08-23
• Reusing an existing Click tool with register_commands - 2021-11-29
• Crawling Datasette with Datasette - 2022-02-27
• Registering new Datasette plugin hooks by defining them in other plugins - 2022-06-17
• Writing a Datasette CLI plugin that mostly duplicates an existing command - 2022-10-22
• Writing a CLI utility that is also a Datasette plugin - 2022-11-21
• Scraping Reddit and writing data to the Datasette write API - 2023-03-13
• Interactive row selection prototype with Datasette - 2023-03-30
• Exploring Baseline with Datasette Lite - 2023-05-12
• Syntax highlighted code examples in Datasette - 2023-07-01
• Using pytest-httpx to run intercepted requests through an in-memory Datasette instance - 2023-07-24
• Remember to commit when using datasette.execute_write_fn() - 2023-08-31
• Running Datasette on Hugging Face Spaces - 2023-09-08
• Writing Playwright tests for a Datasette Plugin - 2024-01-08
• Using Parseable with Datasette for OpenTelemetry traces - 2026-10-06

jupyter

• Embedding JavaScript in a Jupyter notebook - 2021-01-22
• Running jupyterlab via uv tool install - 2025-03-08

cookiecutter

• Testing cookiecutter templates with pytest - 2021-01-27
• Conditionally creating directories in cookiecutter - 2021-01-27

gis

• Downloading MapZen elevation tiles - 2021-02-04
• Natural Earth in SpatiaLite and Datasette - 2022-03-04
• Using SQL with GDAL - 2023-03-09
• Serving a custom vector web map using PMTiles and maplibre-gl - 2023-10-23

sphinx

• Using sphinx.ext.extlinks for issue links - 2021-02-17
• Adding Sphinx autodoc to a project, and configuring Read The Docs to build it - 2021-08-10
• Format code examples in documentation with blacken-docs - 2022-04-24
• literalinclude with markers for showing code in documentation - 2024-01-10

postgresql

• Show the SQL schema for a PostgreSQL database - 2021-02-23
• Granting a PostgreSQL user read-only access to some tables - 2021-02-26
• Closest locations to a point - 2021-03-22
• Using unnest() to use a comma-separated string as the input to an IN query - 2021-04-10
• Using json_extract_path in PostgreSQL - 2021-04-13
• Constructing GeoJSON in PostgreSQL - 2021-04-24
• Upgrade Postgres.app on macOS - 2024-06-15

mediawiki

• How to run MediaWiki with SQLite on a macOS laptop - 2021-03-06

azure

• Writing an Azure Function that serves all traffic to a subdomain - 2021-03-27

vscode

• Language-specific indentation settings in VS Code - 2021-04-04
• Search and replace with regular expressions in VS Code - 2021-08-02

wikipedia

• The Wikipedia page stats API - 2021-05-13

vega

• Vega-Lite bar charts in the same order as the data - 2021-05-15

spatialite

• KNN queries with SpatiaLite - 2021-05-16
• Creating a minimal SpatiaLite database with Python - 2021-12-17
• GUnion to combine geometries in SpatiaLite - 2022-04-12
• Viewing GeoPackage data with SpatiaLite and Datasette - 2022-12-11

sql

• Finding duplicate records by matching name and nearby distance - 2021-05-19
• Building a Markdown summary of Django group permissions - 2021-06-03
• Cumulative total over time in SQL - 2021-09-13
• Using recursive CTEs to explore hierarchical Twitter threads - 2023-01-30
• Consecutive groups in SQL using window functions - 2023-06-08

amplitude

• Exporting Amplitude events to SQLite - 2021-06-06

vim

• Mouse support in vim - 2021-06-19

reddit

• Scraping Reddit via their JSON API - 2021-06-21

nginx

• Using nginx to proxy to a Unix domain socket - 2021-07-10

tesseract

• Using the tesseract CLI tool - 2021-07-18

imagemagick

• Set a GIF to loop using ImageMagick - 2021-08-03
• Compressing an animated GIF with gifsicle or ImageMagick mogrify - 2021-08-05

observable-plot

• Histogram with tooltips in Observable Plot - 2021-08-21
• Wider tooltip areas for Observable Plot - 2022-11-21

purpleair

• Calculating the AQI based on the Purple Air API for a sensor - 2021-08-31

electron

• Using the Chrome DevTools console as a REPL for an Electron app - 2021-08-31
• Open external links in an Electron app using the system browser - 2021-09-02
• Signing and notarizing an Electron app for distribution using GitHub Actions - 2021-09-08
• Bundling Python inside an Electron app - 2021-09-08
• Configuring auto-update for an Electron app - 2021-09-13
• Testing Electron apps with Playwright and GitHub Actions - 2022-07-13

googlecloud

• Publishing to a public Google Cloud bucket with gsutil - 2021-09-20
• Google OAuth for a CLI application - 2022-02-16
• Recursively fetching metadata for all files in a Google Drive folder - 2022-02-16
• Analyzing Google Cloud spend with Datasette - 2022-08-16
• Workaround for google-github-actions/setup-gcloud errors - 2022-12-01
• Reading thermometer temperatures over time from a video - 2023-04-02

git

• Removing a git commit and force pushing to remove it from history - 2021-10-22
• Rewriting a repo to contain the history of just specific files - 2022-03-22
• git bisect - 2022-10-29
• How to create a tarball of a git repository using "git archive" - 2022-11-15
• Rewriting a Git repo to remove secrets from the history - 2023-01-24
• Using git-filter-repo to set commit dates to author dates - 2023-07-10
• Back-dating Git commits based on file modification dates - 2024-08-01
• Calculating the size of all LFS files in a repo - 2024-12-25

web-components

• Understanding Kristofer Joseph's Single File Web Component - 2021-10-27

kubernetes

• Basic Datasette in Kubernetes - 2021-11-05
• kubectl proxy - 2021-12-28

deno

• Annotated code for a demo of WebSocket chat in Deno Deploy - 2021-11-06
• Deno KV - 2023-04-28
• Running Python code in a Pyodide sandbox via Deno - 2023-05-10

fly

• Assigning a custom subdomain to a Fly app - 2021-11-20
• Using the undocumented Fly GraphQL API - 2022-01-21
• Using the Fly Docker registry - 2022-05-21
• Writing Fly logs to S3 - 2022-05-25
• Wildcard DNS and SSL on Fly - 2022-05-25
• Deploying a redbean app to Fly - 2022-07-24
• How to scp files to and from Fly - 2022-09-02
• Configuring Django SQL Dashboard for Fly PostgreSQL - 2023-08-21
• Deploying the CLIP embedding model on Fly - 2023-10-18
• Running Varnish on Fly - 2024-01-08

caddy

• Pausing traffic and retrying in Caddy - 2021-11-24

npm

• Publishing a Web Component to npm - 2021-11-28
• Annotated package.json for idb-keyval - 2022-02-10
• Upgrading packages with npm - 2022-07-13
• Running self-hosted QuickJS in a browser - 2024-03-20
• Running Prettier against Django or Jinja templates - 2024-06-19
• Publishing a simple client-side JavaScript package to npm with GitHub Actions - 2024-12-07

pluggy

• Registering the same Pluggy hook multiple times in a single file - 2021-12-16

cloudflare

• Adding a robots.txt using Cloudflare workers - 2021-12-21
• How to get Cloudflare to cache HTML - 2024-01-08
• Redirecting a whole domain with Cloudflare - 2024-03-15
• Cloudflare redirect rules with dynamic expressions - 2024-05-29
• Setting cache-control: max-age=31536000 with a Cloudflare Transform Rule - 2024-10-23
• GitHub OAuth for a static site using Cloudflare Workers - 2024-11-28
• Redirecting a domain using Cloudflare Pages - 2025-05-28
• Rate limiting by IP using Cloudflare's rate limiting rules - 2025-07-03
• Cloudflare response header transform rules - 2026-01-23
• Cloudflare CAPTCHA on at least one ampersand - 2026-06-15

webauthn

• WebAuthn browser support - 2021-12-29

pixelmator

• Pixel editing a favicon with Pixelmator - 2022-01-20

graphql

• get-graphql-schema - 2022-02-01
• Using curl to run GraphQL queries from the command line - 2022-02-21
• GraphQL fragments - 2022-09-30

google-sheets

• Concatenating strings and newlines in Google Sheets - 2022-03-15
• SQL functions in Google Sheets to fetch data from Datasette - 2026-04-19

twitter

• Exporting and editing a Twitter Spaces recording - 2022-03-23
• How to get credentials for a new Twitter bot - 2022-04-17
• Loading Twitter Birdwatch into SQLite for analysis with Datasette - 2022-09-03
• Collecting replies to tweets using JavaScript - 2024-10-08

shot-scraper

• Extracting web page content using Readability.js and shot-scraper - 2022-03-24
• shot-scraper for a subset of table columns - 2022-10-14
• Scraping the Sky News Westminster Accounts, a Flourish application - 2023-01-10
• Social media cards generated with shot-scraper - 2023-04-29
• axe-core and shot-scraper for accessibility audits - 2023-07-30

auth0

• Simplest possible OAuth authentication with Auth0 - 2022-03-26
• Logging users out of Auth0 - 2022-04-03

webassembly

• Compiling to WASM with llvm on macOS - 2022-03-28
• Run Python code in a WebAssembly sandbox - 2023-02-02

service-workers

• Intercepting fetch in a service worker - 2022-04-30

networking

• Making HTTP calls using IPv6 - 2022-06-08
• Running Ethernet over existing coaxial cable - 2024-02-12

gpt3

• Using GPT-3 to figure out jq recipes - 2022-08-10
• Guessing Amazon image URLs using GitHub Copilot - 2022-10-15
• Generating OpenAPI specifications using GPT-3 - 2022-11-13
• Writing tests with Copilot - 2022-11-14
• Reformatting text with Copilot - 2022-12-09
• A simple Python wrapper for the ChatGPT API - 2023-03-02
• Using ChatGPT to write AppleScript - 2023-03-08
• Using the ChatGPT streaming API from Python - 2023-04-01
• GPT-4 for API design research - 2023-04-06
• Using ChatGPT Browse to name a Python package - 2023-06-18
• Using OpenAI functions and their Python library for data extraction - 2023-07-09

quarto

• Trying out Quarto on macOS - 2022-08-18

duckdb

• Using DuckDB in Python to access Parquet data - 2022-09-16
• Use DuckDB to convert parquet to JSON and then open it in Datasette Lite - 2023-03-21
• Summing columns in remote Parquet files using DuckDB - 2023-11-14

awslambda

• Deploying Python web apps as AWS Lambda functions - 2022-09-18

cocktails

• Whisky sour - 2022-09-25
• Tommy's Margarita - 2022-10-02
• Pisco sour - 2022-10-08

html

• HTML video that loads when the user clicks play - 2022-09-29
• HTML datalist - 2022-11-14
• Lazy loading images in HTML - 2022-11-26
• Scroll to text fragments - 2023-08-08
• HTML video with subtitles - 2024-07-31

mastodon

• Getting Mastodon running on a custom domain - 2022-11-02
• Export a Mastodon timeline to SQLite - 2022-11-04
• Verifying your GitHub profile on Mastodon - 2022-11-16
• Building Mastodon bots with GitHub Actions and toot - 2023-02-02

json

• JSON Pointer - 2022-11-14
• Processing a stream of chunks of JSON with ijson - 2023-08-15
• Streaming output of an indented JSON array - 2023-08-29

clickhouse

• Querying the GitHub archive with the ClickHouse playground - 2022-12-31
• Reviewing your history of public GitHub repositories using ClickHouse - 2024-03-20

cooking

• Breakfast tacos with eggs, vegetarian sausages and avocado sauce - 2023-01-02

llms

• Running nanoGPT on a MacBook M2 to generate terrible Shakespeare - 2023-02-01
• Training nanoGPT entirely on content from my blog - 2023-02-09
• Running LLaMA 7B and 13B on a 64GB M2 MacBook Pro with llama.cpp - 2023-03-10
• A simple Python implementation of the ReAct pattern for LLMs - 2023-03-17
• Running Dolly 2.0 on Paperspace - 2023-04-12
• Expanding ChatGPT Code Interpreter with Python packages, Deno and Lua - 2023-04-30
• mlc-chat - RedPajama-INCITE-Chat-3B on macOS - 2023-05-22
• Running OpenAI's large context models using llm - 2023-06-13
• Storing and serving related documents with openai-to-sqlite and embeddings - 2023-08-14
• Embedding paragraphs from my blog with E5-large-v2 - 2023-09-08
• Summarizing Hacker News discussion themes with Claude and LLM - 2023-09-09
• Using llama-cpp-python grammars to generate JSON - 2023-09-12
• Exploring ColBERT with RAGatouille - 2024-01-27
• Piping from rg to llm to answer questions about code - 2024-02-11
• How streaming LLM APIs work - 2024-09-21
• Running prompts against images, PDFs, audio and video with Google Gemini - 2024-10-23
• Generating documentation from tests using files-to-prompt and LLM - 2024-11-05
• Named Entity Resolution with dslim/distilbert-NER - 2024-12-23
• Running a gpt-oss eval suite against LM Studio on a Mac - 2025-08-16
• Exploring OpenAI's deep research API model o4-mini-deep-research - 2025-10-18
• Using Codex CLI with gpt-oss:120b on an NVIDIA DGX Spark via Tailscale - 2025-11-06
• Running OpenClaw in Docker - 2026-02-01
• Using LLM in the shebang line of a script - 2026-05-11
• Setting a custom price for a model in AgentsView - 2026-06-09
• Adding a custom MCP server to Claude and ChatGPT - 2026-07-28
• Using Blender with coding agents on macOS - 2026-09-05

ab

• Avoiding "length" errors in Apache Bench with the -l option - 2023-02-08

hacker-news

• How to read Hacker News threads with most recent comments first - 2023-03-12

observable

• Using jq in an Observable notebook - 2023-03-25

midjourney

• Creating desktop backgrounds using Midjourney - 2023-04-10

exif

• Interpreting photo orientation and locations in EXIF data - 2023-04-22

misc

• hexdump and hexdump -C - 2023-05-22
• Cloning my voice with ElevenLabs - 2023-11-15

http

• Testing the Access-Control-Max-Age CORS header - 2023-05-25

discord

• A Discord bot to expand issue links to a private GitHub repository - 2023-06-29

yaml

• Auto-formatting YAML files with yamlfmt - 2023-07-13

overture-maps

• Exploring the Overture Maps places data using DuckDB, sqlite-utils and Datasette - 2023-07-27

cosmopolitan

• Catching up with the Cosmopolitan ecosystem - 2023-08-10

google

• Limited JSON API for Google searches using Programmable Search Engine - 2023-09-16
• Generating URLs to a Gmail compose window - 2024-03-12

machinelearning

• Trying out the facebook/musicgen-small sound generation model - 2023-09-23

css

• Understanding the CSS auto-resizing textarea trick - 2023-09-30
• A simple two column CSS grid - 2023-10-26
• Styling an HTML dialog modal to take the full height of the viewport - 2025-03-14

pyodide

• Cryptography in Pyodide - 2023-11-26

playwright

• Using expect() to wait for a selector to match multiple items - 2024-01-13
• Testing HTML tables with Playwright Python - 2024-09-03

httpx

• Logging OpenAI API requests and responses using HTTPX - 2024-01-26

valtown

• Running a scheduled function on Val Town to import Atom feeds into Datasette Cloud - 2024-02-20

chrome

• Google Chrome --headless mode - 2024-03-24

go

• Installing tools written in Go - 2024-03-25

ham-radio

• How I studied for my Ham radio general exam - 2024-05-11

ios

• Listen to a web page in Mobile Safari - 2024-05-21

youtube

• Livestreaming a community election event on YouTube - 2024-10-09
• Error 153 Video player configuration error on YouTube embeds - 2025-09-30

hugo

• The most basic possible Hugo site - 2024-10-22

uv

• Using uv to develop Python command-line applications - 2024-10-23
• Running pytest against a specific Python version with uv run - 2025-02-04
• Testing different Python versions with uv with-editable and uv-test - 2025-10-08
• Dependency groups and uv run - 2025-12-02

tiktok

• Downloading every video for a TikTok account - 2025-01-18

claude-code

• Using Playwright MCP with Claude Code - 2025-07-01
• Previewing Claude Code for web branches with GitHub Pages - 2026-01-22

neon

• Taking Neon I at the Crucible - 2026-01-11