tcpdump is the premier network analysis tool for information security professionals. Having a solid grasp of this über-powerful application is mandatory for anyone desiring a thorough understanding of TCP/IP.

Some use-cases for building a classifier:

* Spam detection, for example you could build your own Akismet API
* Automatic assignment of categories to a set of items
* Automatic detection of the primary language (e.g. Google Translate)
* Sentiment analysis, which in simple terms refers to discovering if an opinion is about love or hate about a certain topic

In general you can do a lot better with more specialized techniques, however the Naive Bayes classifier is general-purpose, simple to implement and good-enough for most applications. And while other algorithms give better accuracy, in general I discovered that having better data in combination with an algorithm that you can tweak does give better results for less effort.

In this article I'm describing the math behind it. Don't fear the math, as this is simple enough that a high-schooler understands. And even though there are a lot of libraries out there that already do this, you're far better off for understanding the concept behind it, otherwise you won't be able to tweak the implementation in response to your needs.

The amount of user-generated content on the Internet has risen exponentially over the last decade, and such content is now always at our fingertips. As a result, nearly all our decision-making is social; before buying products (attending events, trying services, voting for candidates, visiting specialists), we see what our peers are saying about them. The fate of a new offering is often sealed by those evaluations.

Sentiment analysis, the computational study of how opinions, attitudes, emotions, and perspectives are expressed in language, provides a rich set of tools and techniques for extracting this evaluative, subjective information from large datasets and summarizing it. It can thus be vital to service providers, allowing them to quickly assess how new products and features are being received. Recent breakthroughs mean that this analysis can go beyond a general measure of positive vs. negative, isolating a fuller spectrum of emotions and evaluations and controlling for different topics and community norms.

This tutorial covers all aspects of building effective sentiment analysis systems for textual data, with and without sentiment-relevant metadata like star ratings. We proceed from pre-processing techniques to advanced uses cases, assessing common approaches and identifying best practices.

A simple yesod tutorial. Yesod is a Haskell web framework. You shouldn’t need to know Haskell.

just a simple guide for getting started with git. no deep shit ;)

I have written software professionally in perhaps a dozen programming languages, and the hardest language for me to learn has been R. The language is actually fairly simple, but it is unconventional. These notes are intended to make the language easier to learn for someone used to more commonly used languages such as C++, Java, Perl, etc.

R is more than a programming language. It is an interactive environment for doing statistics. I find it more helpful to think of R as having a programming language than being a programming language. The R language is the scripting language for the R environment, just as VBA is the scripting language for Microsoft Excel. Some of the more unusual features of the R language begin to make sense when viewed from this perspective.

Steve was speaking of operating systems, but his words apply to any clockwork. When lives are on the line, lives you want to destroy, will your laser deathray malfunction? This guide provides tools and techniques for making digital superweapons more robust, more efficient, more deadly.

The HTML source for my (i.e., this) web site lives in a Git repository on my local workstation. This page describes how I set things up so that I can make changes live by running just "git push web".

This is the world's best introduction to sed - the superman of UNIX stream editing.

A Moka Pot (sometimes called a stovetop espresso maker) can be an excellent way to prepare coffee (though it actually does not, in fact, make espresso). Keys to good coffee using a Moka Pot are: using high quality, fresh coffee; pre-heating the water; removing the pot from the heat at the right moment; proper grind of coffee; and using clean equipment.

Scala school was started as a series of lectures at Twitter to prepare experienced engineers to be productive Scala programmers. Being a relatively new language, but also one that draws on many familiar concepts, we found this an effective way of getting new engineers up to speed quickly. This is the written material that accompanied those lectures. We have found that these are useful in their own right.

To this day, 90% of the programmers I talk to have never used awk. Knowing 10% of awk's already small syntax, which you can pick up in just a few minutes, will dramatically increase your ability to quickly manipulate data in text files. Below I'll teach you the most useful stuff - not the "fundamentals", but the 5 minutes worth of practical stuff that will get you most of what I think is interesting in this little language.

These guides help you install, setup and configure a FreeBSD system for use with ZFS.

This web site is an attempt to gather together everything you will need to learn Clojure, assuming that you already know another programming language or two or three.

With his essay Beating the Averages , Paul Graham told the story of how his web start-up Viaweb outperformed its competitors by using Lisp. Lisp? Did I parse that correctly? That ancient language with all those scary parentheses? Yes, indeed! And with the goal of identifying its strengths and what they can do for us, I'll put Lisp to work developing a web application. In the process we'll find out how a 50 years old language can be so well-suited for modern web development and yes, it's related to all those parentheses.

Oh Hello! Welcome to my guide to Erlang! This guide is intended to be read by beginners, but if you're average or somewhat advanced you can probably learn a few things too!

There are other tutorials that are very good, and google will help you find them all. Maybe the greatest need in this world is not for another vim tutorial, but this one is mine.

Welcome to the first part of a series of episodes about ‘Functional Scala’. While positioning itself as a so called object-functional language, most of the discussion and articles about Scala centered around its object oriented features so far. If you’re reading this, chances are you want to learn more about the functional side of Scala. Well, you’ve come to the right place.

The idea for the following episodes arose out of some talks i gave about ‘Functional Scala’. I decided to write and talk about it because I wanted to solidify my own knowledge about Functional Programming in general and about Scala in particular … and because I thought I could help some people new to Scala to learn its functional features from my perspective.

I decided to build a small application that starts as a typical Java development and over a number of versions becomes a full-blown Scala implementation. All versions of the application are maintained so that it becomes possible to step through and see each new level of progression into the Scala way of doing things.

Recently I saw that Uncle Bob had written an Orbit Simulator, so I figured I'd read through it point out a few areas where the code could be more idiomatic, to help out Bob and other Ruby developers looking to take on Clojure.

jQuery is fast becoming a must-have skill for front-end developers. The purpose of this book is to provide an overview of the jQuery JavaScript library; when you're done with the book, you should be able to complete basic tasks using jQuery, and have a solid basis from which to continue your learning. This book was designed as material to be used in a classroom setting, but you may find it useful for individual study.

Git is a distributed version control system. No, you don't need to know what that means to use this guide. Think of it as a time machine: Subversion or CVS without the cruft.

If you make a lot of changes, but decided you made a mistake, this will save your butt.

This guide is for people who want to jump to any point in time with their project/game/whatever, and want something to use for themselves.