negipo

#!/bin/sh

screencapture -m -tjpg ~/tmp/capture.jpg
cat ~/tmp/capture.jpg | perl -npe 's/0/9/g' >~/tmp/glitched_capture.jpg
open /System/Library/Frameworks/ScreenSaver.framework/Resources/ScreenSaverEngine.app # set qtz file shows ~/tmp/glitched_capture.jpg

mojombo

require 'digest/md5'

def gfm(text)
  # Extract pre blocks
  extractions = {}
  text.gsub!(%r{<pre>.*?</pre>}m) do |match|
    md5 = Digest::MD5.hexdigest(match)
    extractions[md5] = match
    "{gfm-extraction-#{md5}}"
  end