hellerbarde

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs

whatisaphone

import hashlib


class FeistelSHA1:
    rounds = 4  # 4 rounds is sufficient as long as the round function is cryptographically secure
    split = 1 / 2

    def __init__(self, key, rounds=rounds):
        self.subkeys = [hashlib.sha1(bytes((i,)) + key).digest() for i in range(rounds)]

MohamedAlaa

tmux shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname

kevin-smets

Default

Powerlevel10k

lelandbatey

Description

This simple script will take a picture of a whiteboard and use parts of the ImageMagick library with sane defaults to clean it up tremendously.

The script is here:

#!/bin/bash
convert "$1" -morphology Convolve DoG:15,100,0 -negate -normalize -blur 0x1 -channel RBG -level 60%,91%,0.1 "$2"

Results

danklammer

/*   Theme Name:  Flat Pinboard                       */
/*   Theme URL:   http://tackk.com/flat-pinboard      */
/*   Version:     v1.0                                */
/*   Created by:  Dan Klammer                         */
/*   Broswer:     Chrome + Stylish Extension          */

html {
	-webkit-font-smoothing:antialiased;
	height:100%;
}

will-hart

"""

Free to use under the MIT license

Builds a static site from a list of Markdown source files. The source
files should have the same directory structure as the desired output.

Files are rendered using Markdown2 and can declare metadata variables:

    ---

katychuang

#!/usr/bin/env sh

# first check to see if mongo service is running. you can't delete any files until the service stops so perform a quick check.
launchctl list | grep mongo
  # NOTE: the pipe | symbol means the commands on the right performs on the output from the left
  # grep is a string search utility. `grep mongo` means search for the substring mongo
 
# use the unload command to end the mongo service. this is required to 'unlock' before removing the service.
#    first look for the file to delete
MONGO_SERVICE_FILE=$(ls ~/Library/LaunchAgents/*mongodb*)

DrRobotmck

{
   "1":{
      "name":"Bulbasaur",
      "attack":49,
      "defense":49,
      "evolveLevel":16,
      "evolveTo":"2",
      "type":"grass",
      "moves":[
         "tackle",

matthewberryman

-- taken from http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Appendix.PostgreSQL.CommonDBATasks.html#Appendix.PostgreSQL.CommonDBATasks.PostGIS
create extension postgis;
create extension fuzzystrmatch;
create extension postgis_tiger_geocoder;
create extension postgis_topology;

alter schema tiger owner to rds_superuser;
alter schema tiger_data owner to rds_superuser;
alter schema topology owner to rds_superuser;