title: bash - how to get (current) Julian day number?
body: <p>How to get today's <a href="http://calendars.wikia.com/wiki/Julian_day_number" rel="nofollow noreferrer">Julian day number (JDN)</a> equivalent? or any date's, for that matter?</p>
  
  <p>I've looked and looked, but only found some functions that produced "year-dayOfYear", not something like: 2457854.</p>