title: How does Linux's mv work internally?
body: <p>I know in Linux, if we want to rename a folder from <code>f_old</code> to <code>f_new</code>, we can run:</p>
  
  <pre><code>mv f_old f_new
  </code></pre>
  
  <p>But this command actually confuses me. Does the system copy all stuff inside <code>f_old</code>, paste it to new folder <code>f_new</code> and delete <code>f_old</code> at last? Or does it just rename <code>f_old</code> to <code>f_new</code>?</p>