Austin Eschenbach eschie

Gmail: delete old emails automatically

Automatically deletes old emails that match the specified label.

Get started

Create a new Google Apps Script at https://script.google.com
Overwrite the placeholder with the javascript below
Update the following constants:
LABEL_TO_DELETE: the label that should be have old messages deleted

What forces layout / reflow

All of the below properties or methods, when requested/called in JavaScript, will trigger the browser to synchronously calculate the style and layout*. This is also called reflow or layout thrashing, and is common performance bottleneck.

Generally, all APIs that synchronously provide layout metrics will trigger forced reflow / layout. Read on for additional cases and details.

Element APIs

Getting box metrics

elem.offsetLeft, elem.offsetTop, elem.offsetWidth, elem.offsetHeight, elem.offsetParent

Benchmarking AngularJS performance

Things to optmize

Use one-time-bind on expressions ( {{::value}} )
Replace $scope.$apply() with $scope.$digest() whenever possible
Move filters to controllers

Measuring Watch list

To get the total watchers on the current page, you can run this script on the browser console:

ffmpeg

Converting Audio into Different Formats / Sample Rates

Minimal example: transcode from MP3 to WMA:
ffmpeg -i input.mp3 output.wma

You can get the list of supported formats with:
ffmpeg -formats

You can get the list of installed codecs with:

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

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!

\

Provider	Singleton	Instantiable	Configurable
Constant	Yes	No	No
Value	Yes	No	No
Service	Yes	No	No
Factory	Yes	Yes	No
Decorator	Yes	No?	No
Provider	Yes	Yes	Yes

Constant

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns                     on recent CPU
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 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs 4X memory

Sessions

New Session

tmux new [-s name] [cmd] (:new) - new session

Switch Session

tmux ls (:ls) - list sessions
tmux switch [-t name] (:switch) - switches to an existing session

	#!/usr/bin/sudo ruby

	#
	# revealer.rb -- Deobfuscate GHE .rb files.
	#
	# This is simple:
	# Every obfuscated file in the GHE VM contains the following code:
	#
	# > require "ruby_concealer.so"
	# > __ruby_concealer__ "..."