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Each of these commands will run an ad hoc http static server in your current (or specified) directory, available at http://localhost:8000. Use this power wisely.

Discussion on reddit.

Python 2.x

$ python -m SimpleHTTPServer 8000

Understanding the Memory Layout of Linux Executables

Required tools for playing around with memory:

hexdump
objdump
readelf
xxd
gcore

How to get a stack trace for each thread in a running python script

Sometimes a python script will simply hang forever with no indication of where things went wrong. Perhaps it's polling a service that will never return a value that allows the program to move forward. Here's a way to see where the program is currently stuck.

Install gdb and pyrasite

Install gdb.

# Redhat, CentOS, etc

###IOS presentedViewController and presentingViewController 傻傻分不清楚

在开发中，我们经常回去present一个或多个ViewControllers, 然后我们会通过.取ViewController的presented或presenting的ViewController。每次都分不清楚，因此写个备忘。

先看官方定义：作为UIViewController的两个属性:

presentedViewController:

#!/usr/bin/env bash

# Assuming OS X Yosemite 10.10.4

# Install XCode and command line tools
# See https://itunes.apple.com/us/app/xcode/id497799835?mt=12#
# See https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man1/xcode-select.1.html
xcode-select --install

Studying for a Tech Interview Sucks, so Here's a Cheat Sheet to Help

This list is meant to be a both a quick guide and reference for further research into these topics. It's basically a summary of that comp sci course you never took or forgot about, so there's no way it can cover everything in depth. It also will be available as a gist on Github for everyone to edit and add to.

Data Structure Basics

###Array ####Definition:

Stores data elements based on an sequential, most commonly 0 based, index.
Based on tuples from set theory.

	// Taken from the commercial iOS PDF framework http://pspdfkit.com.
	// Copyright (c) 2014 Peter Steinberger, PSPDFKit GmbH. All rights reserved.
	// Licensed under MIT (http://opensource.org/licenses/MIT)
	//
	// You should only use this in debug builds. It doesn't use private API, but I wouldn't ship it.

	// PLEASE DUPE rdar://27192338 (https://openradar.appspot.com/27192338) if you would like to see this in UIKit.

	#import <objc/runtime.h>
	#import <objc/message.h>

	// Use Gists to store code you would like to remember later on
	console.log(window); // log the "window" object to the console