title: Difference between login name and user name
body: <p>I searched the man for passwd in order to understand the file structure :</p>
  
  <pre><code>man 5 passwd
  </code></pre>
  
  <p>The man presented that each row contain optional 7 fields, two of them are "login name"  and the other "user name or comment field". </p>
  
  <p>Can anyone explain to me what is the difference between the two?</p>
  
  <p>Thanks in advance! </p>