Coffee Break #17

• https://blog.github.com/2018-03-20-top-10-courses-on-github/ — Online education on GitHub.
• https://www.gnupg.org/howtos/card-howto/en/smartcard-howto-single.html — On Smartcards.
• https://github.com/learnbyexample/Command-line-text-processing/blob/master/ruby_one_liners.md — Text Processing with Ruby on the Command Line.