title: Why ln -sf does not overwrite existing link to directory
body: <p>According to documentation, command <code>ln -f</code> removes existing destination file. Does this mean that if I create a symlink, -f should remove of overwrite any existing symlink at destination?</p>
  
  <p>I have a symlink, say, L, pointing to DIR1 and type <code>ln -sf DIR2 L</code>. But L still points to DIR1. Only after <code>rm L</code> this command creates a link pointing to DIR2.</p>
  
  <p>With symlinks to <strong>files</strong> it behaves as expected.</p>
  
  <p>What's wrong with links to <strong>directories</strong>?
  (bash 4.3.48 on Ubuntu 16.04.2 LTS and Windows WSL)</p>