markuszeller

/**
 * Converts an RGB color value to HSL. Conversion formula
 * adapted from http://en.wikipedia.org/wiki/HSL_color_space.
 * Assumes r, g, and b are contained in the set [0, 255] and
 * returns h, s, and l in the set [0, 1].
 *
 * @param   Number  r       The red color value
 * @param   Number  g       The green color value
 * @param   Number  b       The blue color value
 * @return  Array           The HSL representation

markuszeller

/*
 * Easing Functions - inspired from http://gizma.com/easing/
 * only considering the t value for the range [0, 1] => [0, 1]
 */
EasingFunctions = {
  // no easing, no acceleration
  linear: function (t) { return t },
  // accelerating from zero velocity
  easeInQuad: function (t) { return t*t },
  // decelerating to zero velocity

markuszeller

markuszeller

# https://ffmpeg.org/ffmpeg-filters.html#showwaves

# loop 20 times
ffmpeg -stream_loop 20 -i loop.mp4 -c copy output.mp4

# Oscilloscope
ffmpeg -i audio.wav -filter_complex "[0:a]showwaves=s=800x80:mode=p2p:rate=60:draw=full:colors=white,format=rgba[v]" -map "[v]" -map 0:a video.mkv

# Oscilloscope with transparent background
ffmpeg -i audio.wav -filter_complex "[0:a]showwaves=s=800x80:mode=p2p:rate=60:draw=full:colors=white,format=rgba[v]" -map "[v]" -map 0:a -c:v png video.mp4

markuszeller

Keybase proof

I hereby claim:

• I am markuszeller on github.
• I am markuszeller (https://keybase.io/markuszeller) on keybase.
• I have a public key whose fingerprint is D922 1A83 8148 0FAA F776 53B0 E282 0FF5 5AEF BC18

To claim this, I am signing this object:

markuszeller

find . -type f -print -exec shred -u {} \;

markuszeller

Update

sudo apt update
sudo apt upgrade

Try to upgrade dist

sudo apt dist-upgrade
sudo apt autoremove

markuszeller

Avoiding prompts

To avoid any prompts from Debian packages like Grub or mySQL, you can temporarily set an environment variable. This ideal for provisioning scripts in Containers like Vagrant/Docker.

export DEBIAN_FRONTEND="noninteractive"

Also make sure to auto confirm apt with the -y parameter

apt -y upgrade

markuszeller

Remove a file from git repository

This will rewrite the complete history and remove a file from history. This is useful if you have a repository and added files you want to remove for reasons like accidential credentials or too large files (github now supports up to 100MB).

Use following command in your bash

git filter-branch -f --index-filter 'git rm --cached --ignore-unmatch FILENAME' HEAD
git gc --aggresive
git push

markuszeller

WSL Desktop Apps

You can run Apps that require a desktop or a display manager in wsl.exe the Linux Sub System under Windows.

To approach this:

• install a x11 server like xming
• run the display server (under Windows)
• set the environment variable export DISPLAY=localhost:0.0 or better place in ~/.bashrc.
• I recommend adding sudo apt install gitk gedit (This will install many packages)