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@chrisdone
chrisdone / gist:02e165a0004be33734ac2334f215380e
Last active April 16, 2025 07:20
Build and run minimal Linux / Busybox systems in Qemu

Common

export OPT=/opt
export BUILDS=/some/where/mini_linux
mkdir -p $BUILDS

Linux kernel

@zsiegel
zsiegel / systemd-example.md
Last active May 9, 2020 01:20
systemd example - works on Ubuntu 16.04

Ubuntu 16.04 systemd service setup

Enable persistent user systemd services

loginctl enable-linger $user

Create a user systemd directory

mkdir -p ~/.config/systemd/user

FWIW: I (@rondy) am not the creator of the content shared here, which is an excerpt from Edmond Lau's book. I simply copied and pasted it from another location and saved it as a personal note, before it gained popularity on news.ycombinator.com. Unfortunately, I cannot recall the exact origin of the original source, nor was I able to find the author's name, so I am can't provide the appropriate credits.


Effective Engineer - Notes

What's an Effective Engineer?

@neufuture
neufuture / chirp_basic.ino
Last active August 29, 2015 14:14
Arduino code for Chrip moisture sensor
#include <Wire.h>
void writeI2CRegister8bit(int addr, int value) {
Wire.beginTransmission(addr);
Wire.write(value);
Wire.endTransmission();
}
unsigned int readI2CRegister16bit(int addr, int reg) {
Wire.beginTransmission(addr);
@mjquinlan2000
mjquinlan2000 / Gemfile
Last active February 2, 2016 12:32
Proxy multipart/form-data requests through Rails controller to foreign API using Faraday and Dropzone
# Make sure to add this to your Gemfile
gem 'faraday'
@alanhamlett
alanhamlett / api.py
Last active October 21, 2024 14:30
Serialize SQLAlchemy Model to dictionary (for JSON output) and update Model from dictionary attributes.
import uuid
import wtforms_json
from sqlalchemy import not_
from sqlalchemy.dialects.postgresql import UUID
from wtforms import Form
from wtforms.fields import FormField, FieldList
from wtforms.validators import Length
from flask import current_app as app
from flask import request, json, jsonify, abort
@aras-p
aras-p / preprocessor_fun.h
Last active April 29, 2025 01:49
Things to commit just before leaving your job
// Just before switching jobs:
// Add one of these.
// Preferably into the same commit where you do a large merge.
//
// This started as a tweet with a joke of "C++ pro-tip: #define private public",
// and then it quickly escalated into more and more evil suggestions.
// I've tried to capture interesting suggestions here.
//
// Contributors: @r2d2rigo, @joeldevahl, @msinilo, @_Humus_,
// @YuriyODonnell, @rygorous, @cmuratori, @mike_acton, @grumpygiant,
# Raw transaction API example work-through
# Send coins to a 2-of-3 multisig, then spend them.
#
# For this example, I'm using these three keypairs (public/private)
# 0491bba2510912a5bd37da1fb5b1673010e43d2c6d812c514e91bfa9f2eb129e1c183329db55bd868e209aac2fbc02cb33d98fe74bf23f0c235d6126b1d8334f86 / 5JaTXbAUmfPYZFRwrYaALK48fN6sFJp4rHqq2QSXs8ucfpE4yQU
# 04865c40293a680cb9c020e7b1e106d8c1916d3cef99aa431a56d253e69256dac09ef122b1a986818a7cb624532f062c1d1f8722084861c5c3291ccffef4ec6874 / 5Jb7fCeh1Wtm4yBBg3q3XbT6B525i17kVhy3vMC9AqfR6FH2qGk
# 048d2455d2403e08708fc1f556002f1b6cd83f992d085097f9974ab08a28838f07896fbab08f39495e15fa6fad6edbfb1e754e35fa1c7844c41f322a1863d46213 / 5JFjmGo5Fww9p8gvx48qBYDJNAzR9pmH5S389axMtDyPT8ddqmw
# First: combine the three keys into a multisig address:
./bitcoind createmultisig 2 '["0491bba2510912a5bd37da1fb5b1673010e43d2c6d812c514e91bfa9f2eb129e1c183329db55bd868e209aac2fbc02cb33d98fe74bf23f0c235d6126b1d8334f86","04865c40293a680cb9c020e7b1e106d8c1916d3cef99aa431a56d253e69256dac09ef122b1a9
@jboner
jboner / latency.txt
Last active April 29, 2025 15:40
Latency Numbers Every Programmer Should Know
Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference 0.5 ns
Branch mispredict 5 ns
L2 cache reference 7 ns 14x L1 cache
Mutex lock/unlock 25 ns
Main memory reference 100 ns 20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy 3,000 ns 3 us
Send 1K bytes over 1 Gbps network 10,000 ns 10 us
Read 4K randomly from SSD* 150,000 ns 150 us ~1GB/sec SSD
@mediabounds
mediabounds / floatsign.sh
Last active April 15, 2025 12:08
A small bash script to re-sign iOS applications.
# !/bin/bash
# Copyright (c) 2011 Float Mobile Learning
# http://www.floatlearning.com/
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the "Software"),
# to deal in the Software without restriction, including without limitation
# the rights to use, copy, modify, merge, publish, distribute, sublicense,
# and/or sell copies of the Software, and to permit persons to whom the