hack3r-0m

title	subtitle	author	date	source
npm vs Yarn Command Translation Cheat Sheet	CLI commands comparison	yarn	February 15, 2020	https://yarnpkg.com/en/docs/migrating-from-npm

npm vs Yarn Command Translation Cheat Sheet

Editing remote files in Vim with SSH

Configure SSH

In ~/.ssh/config, include the lines:
```
Host *
ControlPath ~/.ssh/sockets/%r@%h-%p
```

Previously described at: ERC20 critical problems medium article.

Description.

ERC20 is the most common Ethereum token standard. It should be noted that it is also the first Ethereum's token standard as well.

It is also important that the original ERC20 proposal is a definition of token interface. EIP20 does not define a reference implementation for this token standard. Here is OpenZeppelin implementation of ERC20 token: https://github.com/OpenZeppelin/zeppelin-solidity/tree/master/contracts/token/ERC20

ERC20 token standard implementation assumes two ways of token transferring: (1) transfer function and (2) approve + transferFrom pattern.

Get pbcopy and pbpaste in Arch Linux

First you need the 'xsel' package.

$> pacman -S xsel

Then create aliases.

alias pbcopy='xsel --clipboard --input'

alias pbpaste='xsel --clipboard --output'

Introduction

The computer driven markets for instruments like stocks and exchange traded stock options, have transformed finance and the flow of capital. These markets are enabled by order matching engines (and the infrastructure that supports this software). Before computer trading networks and matching engines, stocks where traded on cavernous exchange floors and transaction costs where high. When electronic trading fully matured, floor traders were a fading anachronism and transaction costs had been reduced to pennies a share in many cases. Electronic trading could not exist without advanced network infrastructure, but without the software matching engines no shares would change hands. The computer trading networks, the matching engine software has also created a concentrated nexus of potential failure. Failures in these systems have increased as the frequency and volume on the electronic networks has increased. The position of order matching engines in the trading infrastructure makes these systems o

	# Add the following to your existing VPC CF stack

	# create 2 subnets, lambdas like to be in multiple subnets
	Private1:
	Type: AWS::EC2::Subnet
	Properties:
	VpcId: !Ref VPC
	AvailabilityZone: !Select [ 0, !GetAZs ]
	CidrBlock: !Ref Private1CIDR

	// This file is MIT Licensed.
	//
	// Copyright 2017 Christian Reitwiessner
	// 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 Software is furnished to do so, subject to the following conditions:
	// The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
	// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF O

	pragma solidity ^0.4.15;


	contract StringsAndBytes {

	/* --- public variables for storing tests results */
	string public lastTestStringResult; //
	bytes32 public lastTestBytes32Result; //
	bytes public lastTestBytesResult; // bytes: dynamically-sized byte array
	bool public lastTestBoolResult; //

	function watchEtherTransfers() {
	// Instantiate web3 with WebSocket provider
	const web3 = new Web3(new Web3.providers.WebsocketProvider('wss://rinkeby.infura.io/ws'))

	// Instantiate subscription object
	const subscription = web3.eth.subscribe('pendingTransactions')

	// Subscribe to pending transactions
	subscription.subscribe((error, result) => {
	if (error) console.log(error)

	worker_processes auto;
	events {
	# Allows up to 1024 connections, can be adjusted
	worker_connections 1024;
	}

	# RTMP configuration
	rtmp {
	server {
	listen 1935; # Listen on standard RTMP port