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echo -e '"$RANDOM returns a pseudorandom integer between 0 and 32767" - False.'
(( r = 1 ))
until ((r <= 0 || r >= 32767))
do
(( r = $RANDOM ))
done
echo -e "$r.\nSemicolons replace newlines:"
(( r = 5)); while ((r < 10)); do echo $r; (( r ++ )); done
echo "Ranges include end:"
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CTimmerman / pygame-play-tone.py
Created January 18, 2021 19:22 — forked from ohsqueezy/pygame-play-tone.py
Play a 440 Hz tone in Pygame
# Generate a 440 Hz square waveform in Pygame by building an array of samples and play
# it for 5 seconds. Change the hard-coded 440 to another value to generate a different
# pitch.
#
# Run with the following command:
# python pygame-play-tone.py
from array import array
from time import sleep
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CTimmerman / Jenkinsfile.groovy
Created December 15, 2020 04:37 — forked from Faheetah/Jenkinsfile.groovy
Jenkinsfile idiosynchrasies with escaping and quotes
node {
echo 'Results included as an inline comment exactly how they are returned as of Jenkins 2.121, with $BUILD_NUMBER = 1'
echo 'No quotes, pipeline command in single quotes'
sh 'echo $BUILD_NUMBER' // 1
echo 'Double quotes are silently dropped'
sh 'echo "$BUILD_NUMBER"' // 1
echo 'Even escaped with a single backslash they are dropped'
sh 'echo \"$BUILD_NUMBER\"' // 1
echo 'Using two backslashes, the quotes are preserved'
sh 'echo \\"$BUILD_NUMBER\\"' // "1"
@CTimmerman
CTimmerman / fail.md
Last active April 10, 2025 12:50
Tech fails

If you don't learn from the past you're doomed to repeat it.

Audio

  • Dell
  • Latitude 5501 sounds even worse than my MSI MS-16P7 due to ratting its plastic case. Interviews sound like a poor phone connection. Iron Maiden - Can I Play With Madness on the other hand is tolerable and even has some bass, almost enough for Robbie Williams - Angels, which sounds like a not-quite-tuned FM radio for the vocals (too little power), particularly noticable on U2 - Discotheque. Without "audio enhancements" disabled, its audio jack adds a rumble to videos like this. Worst audio hardware I've ever used, especially playing this. Then again, using my
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CTimmerman / http_ear.py
Created November 24, 2020 09:19
Simple debugging HTTP server
#coding: utf8
""" Simple debugging HTTP server
2020-11-20 v1.0 by Cees Timmerman
"""
import logging
from pprint import pformat as pf
from flask import Flask, request, make_response
app = Flask(__name__)
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CTimmerman / penta.py
Created November 24, 2020 07:57
Euler's pentagonal formula
"""Euler's pentagonal formula, by Cees Timmerman, 2020-11-23.
https://www.youtube.com/watch?v=iJ8pnCO0nTY"""
import math
def get_lookback_index(x: int):
i = 0
a = 0
b = 1
steps = [1]
while i < x-1:
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CTimmerman / App.jsx
Created November 18, 2020 20:52
GIF Maker
// from https://fireship.io/lessons/wasm-video-to-gif/
// formatted using prettier --write "src/**/*.{js,jsx}"
import React, { useState, useEffect } from 'react';
import './App.css';
import { createFFmpeg, fetchFile } from '@ffmpeg/ffmpeg';
const ffmpeg = createFFmpeg({ log: true });
function App() {
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CTimmerman / keybindings.json
Last active June 28, 2023 13:22
Visual Studio Code settings
[
{
"key": "ctrl+f9",
"command": "editor.debug.action.goToNextBreakpoint"
},
{
"key": "ctrl+shift+f9",
"command": "editor.debug.action.goToPreviousBreakpoint"
},
{
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CTimmerman / coal_vs_coal_ash_energy_content.md
Last active March 18, 2024 20:32
Coal ash contains more energy than was gained from burning the coal.

Coal ash contains more energy than was gained from burning the coal.

https://www.world-nuclear.org/information-library/facts-and-figures/heat-values-of-various-fuels.aspx

Natural uranium, in FNR                28,000,000 MJ/kg [so 28e9 J/g]
Hard black coal (IEA definition)            >23.9 MJ/kg
Hard black coal (Australia & Canada)        c. 25 MJ/kg [so 25e3 J/g and 207.25 g/mol according to https://pubchem.ncbi.nlm.nih.gov/compound/1-Anthrylmethanolate]
Sub-bituminous coal (IEA definition)    17.4-23.9 MJ/kg
Sub-bituminous coal (Australia & Canada)    c. 18 MJ/kg
Lignite/brown coal (IEA definition)         <17.4 MJ/kg
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CTimmerman / get_good.txt
Created May 7, 2020 17:10
How to get good.
https://www.youtube.com/watch?v=Y_B6VADhY84
1: Test early and often so you know where you were wrong.
2: Space out sessions so you know it's long term knowledge.
3: Do other stuff in between so it doesn't get boring.