title: How to output text in the R console without creating new lines?
body: <p>I would like to output a progress indicator during my lengthy running algorithms. I can easily "bubble up" a progress value from within my algorithm (e.g. via invoking a provided function callback specifically for this purpose), but the difficulty is in the actual text output process. Every call to <code>print</code> creates a new line, and each prefixed with <code>[1]</code>.</p>
  
  <p><strong>Is there a way to print at different moments in time, without introducing line breaks?</strong></p>
  
  <p>To be concrete, I want to achieve an "animation" that would look like the following if observed at two different times.</p>
  
  <pre><code>0%...
  </code></pre>
  
  <p>...</p>
  
  <pre><code>0%...2%...4%...
  </code></pre>