TIL

i3 config 

set $mod Mod4 # Windows key

Then press $mod+Shift+R to reload config

ssh key pairs (2025-12-09)

  1. Check for id_rsa: ls ~/.ssh (if there, skip to 3.)
  2. Make ssh key ssh-keygen
  3. Copy to server ssh-copy-id {YOU}@server
  4. If on Windows or doing for another account:
    1. copy id_rsa.pub to /home/{USER}/.ssh/authorized_keys
    2. folder permissions: chmod 700 .ssh
    3. file permissions: chmod 600 .ssh/authorized_keys

.git/info/exclude (2025-12-02)

Add files to .git/info/exclude for a private, uncommitted gitignore

lazygit is the best (2025-11-27)

The Performance Inequality Gap, 2026 (2025-11-24)

https://infrequently.org/2025/11/performance-inequality-gap-2026/

Budget @ P75 Total JS (15%) Total JS (50%)
3 sec 2.0 MiB 0.3 MiB 1.2 MiB 0.62 MiB
5 sec 3.7 MiB 0.57 MiB 2.3 MiB 1.15 MiB

Updated network test parameters for 2026 are:

The goal of these recommendations is to emulate a 75th percentile user experience, meaning a full quarter of devices and networks will perform worse than this baseline.

Per usual, we consider pages built in two styles:

Git: Conventional Commits

From Conventional Commits and Angular's convention

Prefix commit messages with meaningful tags. Start with a type, add a (scope), and end with ! if it's a breaking change. i.e., fix(css): saved items not underlined or feat(config)!: switch to YAML.

JS: ??= 

function memoize(fn) {
    const known = [];
    return (num) => (known[num] ??= fn(num));
}

It's beautiful.

Outlook conversations (2025-07-29)

Outlook can only group by conversation when sorted by Date. Sorting by Category completely breaks the grouping.

git bisect (2025-03-28)

If you know a bug was introduced between two releases, you can find it quickly:

  1. git bisect start
  2. git bisect good {tag/commit}
  3. git bisect bad {tag/commit}
  4. Test: git bisect good or git bisect bad (or git bisect skip)
  5. git stash and git stash pop if you need test code.

A Great Joke (2025-03-27)

In the late '90s, the USA was trying to build a super collider in Texas. They needed to get a foreign partner on board, but no countries came forward... until it was suggested that Russia's dirt-cheap manufacturing could be used to produce components at massive discounts, and those discounts could be viewed as their cash contributions. The same labs once used to develop ballistic missiles would now be used to build detector components.

A Russian physicist at the SSC joked by saying "Why, this is nothing new. For many years we made high-precision components for delivery to the United States".

Source: https://www.youtu.be/3xSUwgg1L4g; Part 2 - Bush.

Git undos (2025-02-24)

https://retcon.app/

Undo: created a commit

  1. Run git reset --soft HEAD~.

Undo: deleted a commit

  1. Run git reflog to display the list of recent head commits.
  2. Copy the first one's hash.
  3. Run git reset, then git stash to set changes aside.
  4. Run git reset --hard COPIED_HASH to revert to the previous head commit.
  5. Run git stash pop to restore stashed changes.

Undo: rebased a branch (reword, move, delete, fixup)

  1. See above.

Undo: pulled from a remote

  1. See above.

Undo: pushed to a remote

  1. Find the output of the git push command to undo.
  2. On the last line of the output, copy the first commit hash.
  3. Run git push force COPIED_HASH.
  4. If the remote branch was changed since your push, the new changes will silently be overwritten.

Undo: created a branch

  1. Run git branch -d BRANCH_NAME.

Undo: deleted a branch

  1. Find the output of the git branch -d command to undo.
  2. Copy the commit hash.
  3. Run git branch BRANCH_NAME COPIED_HASH.

Undo: staged a file

  1. To unstage the whole file, run git restore --staged FILE_PATH.
  2. To unstage specific hunks, instead run git reset -p FILE_PATH, and manually select the hunks.

Undo: unstaged a file

  1. To stage the whole file, run git add FILE_PATH.
  2. To stage specific hunks, instead run git add -p FILE_PATH, and manually select the hunks.
  3. If some of the staged changes were not in the working directory, they cannot be recovered.

Undo: confirmed a conflict resolution

  1. Abort the current rebase by running git rebase --abort.
  2. Restart the rebase from scratch. Recreate the same rebase list, perform the same message edits, and redo every conflict resolution yourself.

Zoom (2025-02-13)

You can share multiple windows, which will hide switches and other windows but allow multiple apps!

Excel (2025-01-14)

You can reference the same cell in every sheet with =SUM('*'!A1). It will probably expand to a sheet range: =SUM(Demian:Susan!A1).

cosmopolitan (2024-12-08)

fat binaries, including redbean and greenbean : greenbean might only provide a static page (404 for everything else)

Update: cosmopolitan libc (2025-01-12)

Compile C into a fat binary (run on any platform). https://justine.lol/cosmopolitan/index.html

GIT rebase branch (2024-08-07) 

A ── B ── C ┬─ (<- dev)
            │
            └─ D ─ E ─ (<- branch)

git rebase dev {branch} --onto origin/{base}

A ── B ┬─ C ─ (<- dev)
       │
       └─ D ── E ─ (<- branch)

HTML/CSS/JS Playground (2024-07-29)

MDN Playground

CSS Transparent Variable Colors (2024-07-29) 

body {
    color: color-mix(in srgb, var(--color) 50%, transparent);
}

Math: chance statistics (2024-06-27)

Odds:

Chance of Happening X times:

Combinations:

Permutations:

Linux: deleting large folders

Using rsync is 3x faster than rm.

mkdir empty

rsync -aP --delete empty/ target/

HTML: <em> vs <i>

https://developer.mozilla.org/en-US/docs/Web/HTML/Element/em#i_vs._em

SQLITE: LIMIT 0,30

7z update option

https://7-zip.opensource.jp/chm/cmdline/switches/update.htm

7z u {archive} {paths}

Will:

7z excluding folders 

7z.exe a ./Desktop/Documents.20230612.7z \
	./Documents/git/ \
	./Documents/GitHub/ \
	./Documents/htdocs/ \
	./Documents/VILLANOVA/ \
	-xr!node_modules \
	-xr!.git -xr!fonts

Javascript: variable keys in maps 

let x = "apple";

return { [x]: 10 }; // { "apple": 10 }

return { ...state, [x]: 10 };

return { ...state, apples: { [fav]: 10 } };

Python: venv

2023-04-28

Using Python's built in virtual environment means that all libraries are installed locally, allowing you to edit the libraries if understanding or functionality escapes you.

python -m venv ./.venv     ## Creates a virtual env in the current folder

source .venv/bin/activate  ## Activates the venv

PHP multi-thread

One 

// returns the PID of the child to the parent

// the child will receive a 0

$isChildProcess = pcntl_fork() === 0;

if ($isChildProcess) {
	doAsyncTask();
}

Many 

// A pool of threads

foreach ($urls as $index => $page) {
	if (pcntl_fork() === 0) {
		doAsyncTask();
		break; // no grandchildren!
	}
}

Bash Inputs

From Files 

$var = (cat file.txt)

Prompts 

echo -n "username: "
read -r user

echo -n -s "password: "
read -r pwd

SQL: ordered list of values

2021-04-20

You can quickly get an ordered list of ids or values by joining to a temporary table.

SELECT f.id, dbo.professors.* FROM dbo.professors
	JOIN (VALUES (33),(33),(33),(90),(90)) as f(id)
	ON f.id = dbo.professors.professor_id;
id	professor_id	name
33	          33	Sir Isaac Newton
33	          33	Sir Isaac Newton
33	          33	Sir Isaac Newton
90	          90	Carl Sagan
90	          90	Carl Sagan

Javascript: forward declaration (2019-08-20)

Obsolete!

Many linters check for functions to exist before they're referenced. With circular calling, you need to declare a function before it's defined. TIL this is called forward declaration.

let bind = function bindForward() {};

function ajax(url) {
    load(url).then(bind);
}

bind = function bind() {
    $("a").click(ajax);
};

Javascript: Destructuring (2019-08-08)

When destructuring, JS only assigns the deepest nested keys:

const req = { query: { person: { first: "Chris", last: "Hallberg" } } };

const {
    query: {
        person: { first, last },
    },
} = req;

console.log(query); // undefined
console.log(person); // undefined
console.log(first); // "Chris"
console.log(last); // "Hallberg"

You can also assign names that don't match the keys you're grabbing. Just be careful with your brackets.

const req = { query: { data: "apples" } };

// rename query to data
var { query: data } = req;
console.log(data); // { data: "apples" }

// destruct data from query
var {
    query: { data },
} = req;
console.log(data); // apples

Warning: In browsers, name seems to be assigned to "[object Object]" somewhere along the line, so be careful.

Javascript: Destructuring as parameters

2019-09-19

I learned today that you can destructure variables as part of a function declaration or as part of a for-of loop:

function getHeight({ height }) {
    return height;
}

getHeight({ width: 10, height: 200, depth: 7 }); // 200

const points = [
    { x: 3, y: 4 },
    { x: 5, y: 5 },
];

for (let { x, y } of points) {
    console.log(`distSq = ${(x ** 2, y ** 2)}`);
}

// distSq = 25

// distSq = 50

Javascript: Destructuring as default parameters

2019-09-24

It's been a good month for destructuring. Building on the previous revelation, you can set parameter defaults with destructuring.

function showConfig({ tabSize = 2, theme = "Nord" } = {}) {
    console.log(`Theme: ${theme}, Tab Size: ${tabSize}`);
}

showConfig({ tabSize: 4, theme: "Monokai" }); // Theme: Monokai, Tab Size: 4

showConfig({ theme: "Monokai" }); // Theme: Monokai, Tab Size: 2

showConfig(); // Theme: Nord, Tab Size: 2

WebVR

Oculus Quest debugging

A-Frame

2019-09-07

I couldn't find any official way to get debugging info from the Oculus Quest since it only connects over Wi-Fi (if at all) and the SteamVR logs don't pick up anything.

So I dropped a text element into the world and used that as my string log. You can put this element inside the camera if you want it to be visible as a UI element, but I didn't do that.

<a-text id="log" value="Hello!" color="#000" align="center" position="0 2 -5"></a-text>
const logEl = document.getElementById("log");

function log(msg) {
    logEl.setAttribute("value", msg);
}

// For updating messages

function debug() {
    requestAnimationFrame(debug);
    log(blueGun.object3D.matrix.toArray().join(","));
}

requestAnimationFrame(debug);

// For everything else

try {
    // do a backflip
} catch (e) {
    log(e);
}

Move the World, Not the Camera

A-Frame

2019-09-07

I have a few game concepts that involve pulling the player along or changing their view but trying to override the default WebVR camera is a pain.

If you do manage to get control of the camera (either with groups or with rigs) you need to then manually ensure you draw both eye "cameras" anyway. It's just more work that it's worth when you can move the whole world instead!

A heirachy like this makes this quite easy to do:

- scene
  - camera
  - world
	- hand controllers
	- all physical items

Thank you, Stefan Judis for the idea and encouragement.