Nicolas S. Montanaro 99z

Install ImageMagick for image conversion:

brew install imagemagick

Install tesseract for OCR:

brew install tesseract --all-languages

Or install without --all-languages and install them manually as needed.

true and false vs. "truthy" and "falsey" (or "falsy") in Ruby, Python, and JavaScript

Many programming languages, including Ruby, have native boolean (true and false) data types. In Ruby they're called true and false. In Python, for example, they're written as True and False. But oftentimes we want to use a non-boolean value (integers, strings, arrays, etc.) in a boolean context (if statement, &&, ||, etc.).

This outlines how this works in Ruby, with some basic examples from Python and JavaScript, too. The idea is much more general than any of these specific languages, though. It's really a question of how the people designing a programming language wants booleans and conditionals to work.

If you want to use or share this material, please see the license file, below.

Update

OS X Screencast to animated GIF

This gist shows how to create a GIF screencast using only free OS X tools: QuickTime, ffmpeg, and gifsicle.

Instructions

To capture the video (filesize: 19MB), using the free "QuickTime Player" application:

ANNOUNCEMENT

I have moved this over to the Tech Interview Cheat Sheet Repo and has been expanded and even has code challenges you can run and practice against!

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9front tutorials

Current as of 9front-5966.df2c352ae695

This is a collection of notes on how to complete tasks I've found myself commonly performing while using 9front.

Note that most of what is here is straight from various parts of the 9front FQA, just ordered differently. If not from the FQA, I'll provide the source under the header for the section.

As I'm in the process of learning Plan 9/9front, feel free to comment with suggestions or corrections.

	#Model

	@user.should have(1).error_on(:username) # Checks whether there is an error in username
	@user.errors[:username].should include("can't be blank") # check for the error message

	#Rendering
	response.should render_template(:index)

	#Redirecting
	response.should redirect_to(movies_path)

	Nitty Gritty Gameboy Cycle Timing
	---------------------------------


	A document about the down and dirty timing of the Gameboy's video hardware.

	Written by: Kevin Horton
	Version: 0.01 (preliminary)

	My findings here are based on the original DMG, Super Gameboy, and GB

	#!/usr/bin/osascript
	#
	# now_playing.osascript
	#
	# Osascript to fetch the meta data of the currently playing
	# track in Spotify. This works only on Mac OS X.

	tell application "System Events"
	set myList to (name of every process)
	end tell

	// Just before switching jobs:
	// Add one of these.
	// Preferably into the same commit where you do a large merge.
	//
	// This started as a tweet with a joke of "C++ pro-tip: #define private public",
	// and then it quickly escalated into more and more evil suggestions.
	// I've tried to capture interesting suggestions here.
	//
	// Contributors: @r2d2rigo, @joeldevahl, @msinilo, @_Humus_,
	// @YuriyODonnell, @rygorous, @cmuratori, @mike_acton, @grumpygiant,