title: unix command line execute with . (dot) vs. without
body: <p>At a unix command line, what's the difference between executing a program by simply typing it's name, vs. executing a program by typing a . (dot) followed by the program name? e.g.:</p>
  
  <pre><code>runme
  </code></pre>
  
  <p>vs.</p>
  
  <pre><code>. runme
  </code></pre>