kentbrew

The Problem

Standard practices say no non-root process gets to talk to the Internet on a port less than 1024. How, then, could I get Node talking on port 80 on EC2? (I wanted it to go as fast as possible and use the smallest possible share of my teeny tiny little micro-instance's resources, so proxying through nginx or Apache seemed suboptimal.)

The temptingly easy but ultimately wrong solution:

Alter the port the script talks to from 8000 to 80:

}).listen(80);

foogoof

//
// Just skip to the bottom
//

var express = require('express');
var io = require('socket.io');

var app = module.exports = express.createServer();

// Configuration

spicycode

# 0 is too far from ` ;)
set -g base-index 1

# Automatically set window title
set-window-option -g automatic-rename on
set-option -g set-titles on

#set -g default-terminal screen-256color
set -g status-keys vi
set -g history-limit 10000

simme

# First install tmux
brew install tmux

# For mouse support (for switching panes and windows)
# Only needed if you are using Terminal.app (iTerm has mouse support)
Install http://www.culater.net/software/SIMBL/SIMBL.php
Then install https://bitheap.org/mouseterm/

# More on mouse support http://floriancrouzat.net/2010/07/run-tmux-with-mouse-support-in-mac-os-x-terminal-app/

KL-7

One-liners

Reverse every line:

Input file:

$ cat foo
qwe
123

bar

mbostock

license: gpl-3.0

akoumjian

Boostrapping Salt on Linux EC2 with Cloud-Init

Salt is a great tool for remote execution and configuration management, however you will still need to bootstrap the daemon when spinning up a new node. One option is to create and save a custom AMI, but this creates another resource to maintain and document.

A better method for Linux machines uses Canonical's CloudInit to run a bootstrap script during an EC2 Instance initialization. Cloud-init takes the user_data string passed into a new AWS instance and runs it in a manner similar to rc.local. The bootstrap script needs to:

1. Install Salt with dependencies
2. Point the minion to the master

jboner

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

ckirkendall

(use '[clojure.core.match :only [match]])

(defn evaluate [env [sym x y]]
  (match [sym]
    ['Number]   x
    ['Add]      (+ (evaluate env x) (evaluate env y))
    ['Multiply] (* (evaluate env x) (evaluate env y))
    ['Variable] (env x)))
    
(def environment {"a" 3, "b" 4, "c" 5})

MohamedAlaa

tmux shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname