Shankar Nakai Gonçalves dos Santos shankarnakai

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

Basic Steps

Clarify and agree on the scope of the system

User cases (description of sequences of events that, taken together, lead to a system doing something useful)
- Who is going to use it?
- How are they going to use it?

1. Downloading

32 bits version

$ wget https://get.popcorntime.sh/build/Popcorn-Time-0.3.10-Linux-32.tar.xz -O popcorntime.tar.xz

64 bits version

Git Commit Best Practices

Basic Rules

Commit Related Changes

A commit should be a wrapper for related changes. For example, fixing two different bugs should produce two separate commits. Small commits make it easier for other developers to understand the changes and roll them back if something went wrong. With tools like the staging area and the ability to stage only parts of a file, Git makes it easy to create very granular commits.

Commit Often

Committing often keeps your commits small and, again, helps you commit only related changes. Moreover, it allows you to share your code more frequently with others. That way it‘s easier for everyone to integrate changes regularly and avoid having merge conflicts. Having large commits and sharing them infrequently, in contrast, makes it hard to solve conflicts.

	import Debug.Trace

	main :: IO()
	main = do
	let sorted = mergeSort [6, 5, 3, 1, 8, 7, 2, 4]
	print sorted

	mergeSort :: (Ord a, Show a) => [a] -> [a]
	-- mergeSort lst \| trace ("sorting: " ++ show lst) False = undefined
	mergeSort [] = []

	#!/bin/bash
	# higher order functions for bash

	array(){
	declare -A "$@"
	}

	# foreach
	# example:
	# array foo

	// Package deepcopy provides a function for deep copying map[string]interface{}
	// values. Inspired by the StackOverflow answer at:
	// http://stackoverflow.com/a/28579297/1366283
	//
	// Uses the golang.org/pkg/encoding/gob package to do this and therefore has the
	// same caveats.
	// See: https://blog.golang.org/gobs-of-data
	// See: https://golang.org/pkg/encoding/gob/
	package deepcopy

	---
	- name: Install MacOS Packages
	hosts: localhost
	become: false
	vars:
	brew_cask_packages:
	- atom
	- docker
	- dropbox
	- firefox

	; Path of Exile macros

	; go to hideout
	#IfWinActive, Path of Exile
	^h:: Send {Enter}+{Home}^c/hideout{Enter}{Enter}^v{Escape}

	; logout
	#IfWinActive, Path of Exile
	$^l:: Send {Enter}+{Home}^c/exit{Enter}{Enter}^v{Escape}

	#!/bin/bash

	echo "swf2mp4.sh - flash player to mp4 conversion script"
	echo " * Requires gnash, mplayer2 and ffmpeg CLI tools"
	echo " * Source https://stackoverflow.com/a/39304421 (Aleksey Kontsevich)"


	SWFFILE=$1
	MP4FILE=${SWFFILE%.*}.mp4
	TMPFILE=$(cat /dev/urandom \| tr -dc 'a-zA-Z' \| fold -w 32 \| head -n 1).bin

	[
	{
	"name": "[Lorg.eclipse.jetty.servlet.ServletMapping;",
	"allDeclaredFields": true,
	"allPublicFields": true,
	"allDeclaredMethods": true,
	"allPublicMethods": true
	},
	{
	"name": "org.slf4j.impl.StaticLoggerBinder",