knugie

# switching identities in order to use multiple github accounts on one computer, you have to:

# add to ~/.ssh/config according to current github user:
  
  Host github.com
    IdentityFile ~/.ssh/<rsa_id_for_current_user>


# set git user globally or locally according to current github user:
  git config --local user.name "My Name"

knugie

# merge all pdf files from a directory to a single pdf file
pdftk *.pdf cat output out.pdf

# reverse page order of a pdf file
PDFTK_PAGES=$(pdftk in.pdf dump_data | grep NumberOfPages | sed "s/^.*: //")
pdftk in.pdf cat $PDFTK_PAGES-1 output out.pdf

# Strip metadata in pdf
PDFTK_FILE=in.pdf
pdftk $PDFTK_FILE dump_data | sed -e 's/\(InfoValue:\)\s.*/\1\ /g' | pdftk $PDFTK_FILE update_info - output out.pdf

knugie

def rgb2hsl(r,g,b)
  r´ = r.to_f / 255
  g´ = g.to_f / 255
  b´ = b.to_f / 255
  c_max = [r´, g´, b´].max
  c_min = [r´, g´, b´].min
  Δ = c_max - c_min
  h = Δ.zero? ? 0 : (60 * case c_max
    when r´ then ((g´ - b´) / Δ) % 6
    when g´ then ((b´ - r´) / Δ) + 2

knugie

window.cancelRequestAnimFrame = ( function() {
    return window.cancelAnimationFrame          ||
        window.webkitCancelRequestAnimationFrame    ||
        window.mozCancelRequestAnimationFrame       ||
        window.oCancelRequestAnimationFrame     ||
        window.msCancelRequestAnimationFrame        ||
        clearTimeout
} )();

for (var i = 1; i < 99999; i++) {

knugie

sudo apt-get install build-essential pkg-config libc6-dev libssl-dev libexpat1-dev libavcodec-dev libgl1-mesa-dev libqt4-dev
wget http://www.makemkv.com/download/makemkv-oss-1.9.0.tar.gz
wget http://www.makemkv.com/download/makemkv-bin-1.9.0.tar.gz
tar -xvf makemkv-oss-1.9.0.tar.gz
tar -xvf makemkv-bin-1.9.0.tar.gz

cd makemkv-oss-1.9.0/
./configure
make
sudo make install

knugie

ary = [['a', :hello], ['b', :foo], ['b', :bar], ['b', :baz], ['a', :world]]

# QUIZ:
#   How do you sort "ary" so equal objects stay in the same relative order to each other?
#   "ary" should be sorted by the first element of each entry.
#   Try now: http://tryruby.org/

expected = [['a', :hello], ['a', :world], ['b', :foo], ['b', :bar], ['b', :baz]]

# HINT:

knugie

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:

knugie

/*jslint browser: true, indent: 2 */
(function () {
  'use strict';
  var rgb, style, idx = 0, store = {}, tiles = document.getElementById('box').childNodes;
  for (idx; idx < tiles.length; idx += 1) {
    rgb = tiles[idx].style.backgroundColor.split("(")[1].split(")")[0].split(",");
    store[Math.sqrt(Math.pow(rgb[0], 2), Math.pow(rgb[2], 2), Math.pow(rgb[2], 2))] = tiles[idx];
  }
  style = Object.keys(store).map(function (key) { return [key, store[key]]; }).
    sort(function (a, b) { return parseInt(a[0], 10) < parseInt(b[0], 10) ? 1 : -1; })[0][1].style;

knugie

xxd -p org.bin | tr -d '\n' > tmp
xxd -p -r tmp > cpy.bin

knugie

ffmpeg -i in.mts -c:v mpeg4 -qscale:v 5 -acodec libmp3lame -b:a 192k out.mp4