title: Ubuntu base64 encoded string ends with "o=" instead of apparently correct "=="
body: <p>In the instructions on <a href="https://www.polar.com/accesslink-api/?http#token-endpoint" rel="nofollow noreferrer">this OAuth protocol</a>, you can see that the example base64 encoding of "12345:verySecret" is</p>
  
  <p>"MTIzNDU6dmVyeVNlY3JldA=="</p>
  
  <p>The problem is, when I run <code>echo 12345:verySecret | base64</code>I get</p>
  
  <p>"MTIzNDU6dmVyeVNlY3JldAo="</p>
  
  <p>During actual authentication I was banging my head against a wall until I realized I needed to change the second to last "o" character into "=" in my own encoded <em>client_id:client_secret</em> string. But why?</p>