title: What is double dot(..) and single dot(.) in Linux?
body: <p>The <code>ls -ai</code> command shows that <code>.</code> and <code>..</code> have their inodes the same as the current directory and parent directory, respectively.</p>
  
  <p>What exactly are <code>.</code> and <code>..</code>?</p>
  
  <p>Are they real files or even hard links? But as I have known, it's not allowed to create a hard link to a directory.</p>