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@jboner
jboner / latency.txt
Last active April 26, 2024 03:40
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
@myusuf3
myusuf3 / delete_git_submodule.md
Created November 3, 2014 17:36
How effectively delete a git submodule.

To remove a submodule you need to:

  • Delete the relevant section from the .gitmodules file.
  • Stage the .gitmodules changes git add .gitmodules
  • Delete the relevant section from .git/config.
  • Run git rm --cached path_to_submodule (no trailing slash).
  • Run rm -rf .git/modules/path_to_submodule (no trailing slash).
  • Commit git commit -m "Removed submodule "
  • Delete the now untracked submodule files rm -rf path_to_submodule
@hofmannsven
hofmannsven / README.md
Last active April 19, 2024 13:17
Git CLI Cheatsheet
@0mkara
0mkara / Ethereum_private_network.md
Last active April 19, 2024 00:09
Ethereum private network configuration guide.

Create your own Ethereum private network

Introduction

Used nodes:

Linux raspberrypi 4.9.41-v7+ #1023 SMP Tue Aug 8 16:00:15 BST 2017 armv7l GNU/Linux
Linux localhost.localdomain 4.14.5-200.fc26.x86_64 #1 SMP Mon Dec 11 16:29:08 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
@olasd
olasd / stream_to_youtube.sh
Created March 28, 2014 19:58
Stream video to youtube via ffmpeg
#! /bin/bash
#
# Diffusion youtube avec ffmpeg
# Configurer youtube avec une résolution 720p. La vidéo n'est pas scalée.
VBR="2500k" # Bitrate de la vidéo en sortie
FPS="30" # FPS de la vidéo en sortie
QUAL="medium" # Preset de qualité FFMPEG
YOUTUBE_URL="rtmp://a.rtmp.youtube.com/live2" # URL de base RTMP youtube
@P4
P4 / default.reg
Last active April 13, 2024 05:23
Color schemes for Windows Command Prompt
Windows Registry Editor Version 5.00
; Default color scheme
; for Windows command prompt.
; Values stored as 00-BB-GG-RR
[HKEY_CURRENT_USER\Console]
; BLACK DGRAY
"ColorTable00"=dword:00000000
"ColorTable08"=dword:00808080
; BLUE LBLUE
@joepie91
joepie91 / random.md
Last active April 10, 2024 18:45
Secure random values (in Node.js)

Not all random values are created equal - for security-related code, you need a specific kind of random value.

A summary of this article, if you don't want to read the entire thing:

  • Don't use Math.random(). There are extremely few cases where Math.random() is the right answer. Don't use it, unless you've read this entire article, and determined that it's necessary for your case.
  • Don't use crypto.getRandomBytes directly. While it's a CSPRNG, it's easy to bias the result when 'transforming' it, such that the output becomes more predictable.
  • If you want to generate random tokens or API keys: Use uuid, specifically the uuid.v4() method. Avoid node-uuid - it's not the same package, and doesn't produce reliably secure random values.
  • If you want to generate random numbers in a range: Use random-number-csprng.

You should seriously consider reading the entire article, though - it's

@Sjors
Sjors / bitcoin-pay.rb
Last active April 9, 2024 16:50
This script demonstrates how a bitcoin transaction is created and signed. Just pass in your own address and private key and it will prepare a transaction for you. You can then copy & paste that transaction into a webservice like Blockchain to send it. I wrote this mostly to understand better how it works. I sometimes had to "cheat" and look at t…
#!/usr/bin/env ruby
require 'open-uri'
require 'JSON'
require 'digest/sha2'
require 'pry'
require 'bigdecimal'
require 'bitcoin' # Because I need to cheat every now and then
# Usage:
# gem install pry json ffi ruby-bitcoin
@florentbr
florentbr / #wd-drop-file.py
Last active April 7, 2024 02:56
Selenium - Drop a file from the desktop on a drop area
from selenium import webdriver
from selenium.webdriver.remote.webelement import WebElement
import os.path
# JavaScript: HTML5 File drop
# source : https://gist.github.com/florentbr/0eff8b785e85e93ecc3ce500169bd676
# param1 WebElement : Drop area element
# param2 Double : Optional - Drop offset x relative to the top/left corner of the drop area. Center if 0.
# param3 Double : Optional - Drop offset y relative to the top/left corner of the drop area. Center if 0.
# return WebElement : File input