Felx inscapist

An example implementation of the self-pipe trick in Ruby, by Paul Annesley (found here: http://pastebin.com/1SZprwZm)

ANSI Escape Sequences

Standard escape codes are prefixed with Escape:

Ctrl-Key: ^[
Octal: \033
Unicode: \u001b
Hexadecimal: \x1B
Decimal: 27

What do Etcd, Consul, and Zookeeper do?
- Service Registration:
  - Host, port number, and sometimes authentication credentials, protocols, versions numbers, and/or environment details.
- Service Discovery:
  - Ability for client application to query the central registry to learn of service location.
- Consistent and durable general-purpose K/V store across distributed system.
  - Some solutions support this better than others.
  - Based on Paxos or some derivative (i.e. Raft) algorithm to quickly converge to a consistent state.
Centralized locking can be based on this K/V store.

IP Tables (iptables) Cheat Sheet

IPTables is the Firewall service that is available in a lot of different Linux Distributions. While modifiying it might seem daunting at first, this Cheat Sheet should be able to show you just how easy it is to use and how quickly you can be on your way mucking around with your firewall.

Resources

The following list is a great set of documentation for iptables. I used them to compile this documentation.

How-To Geek: The Beginner’s Guide to iptables, the Linux Firewall: https://www.howtogeek.com/177621/the-beginners-guide-to-iptables-the-linux-firewall/
IPTables Essentials: Common Firewall Rules and COmmands https://www.digitalocean.com/community/tutorials/iptables-essentials-common-firewall-rules-and-commands

The netfilter hooks in the kernel and where they hook in the packet flow

The figure below calls out

The netfilter hooks
The order of table traversal

	A Tree is just a restricted form of a Graph.

	Trees have direction (parent / child relationships) and don't contain cycles.
	It has only one path between any two vertices

	They fit with in the category of Directed Acyclic Graphs (or a DAG).
	So Trees are DAGs with the restriction that a child can only have one parent.

	Directed Acyclic Graphs is a kind of directed graph that have no cycles.

	<!DOCTYPE html>
	<html>
	<head>
	<title>Box Shadow</title>

	<style>
	.box {
	height: 150px;
	width: 300px;
	margin: 20px;

	-- Author: Michael-Keith Bernard
	-- Date: August 10, 2012
	--
	-- Notes: This Trie implementation is a port of the Clojure implementation
	-- below. I had to implement quite a few functions from clojure.core to keep the
	-- same basic functionality. Probably very little if any of this code is
	-- production worthy, but it's interesting all the same. Finally, all of the
	-- documentation strings are pulled directly from clojure.core and may not
	-- accurately reflect the Lua implementation.
	--

	let rtcConnection = null;
	let rtcLoopbackConnection = null;
	let loopbackStream = new MediaStream(); // this is the stream you will read from for actual audio output

	const offerOptions = {
	offerVideo: true,
	offerAudio: true,
	offerToReceiveAudio: false,
	offerToReceiveVideo: false,
	};

	package main

	import (
	"database/sql"
	"encoding/json"
	"fmt"
	"reflect"
	"time"

	"github.com/go-sql-driver/mysql"