title: What write into sudoers file to allow USER1 execute specific command as USER2 without password
body: <p>What write into <code>sudoers</code> file to allow <code>USER1</code> execute specific command as <code>USER2</code> without password?</p>
  
  <p><strong>Note that</strong>: </p>
  
  <ol>
  <li>I know that the file should be placed in <code>/etc/sudoers.d/USER1</code></li>
  <li>What permissions and owner should have this file ? <code>600</code> and <code>root:root</code> ?</li>
  </ol>