title: What does -l $_ do in Perl, and how does it work?
body: <p>What is the meaning of the nest code</p>
  
  <pre><code>foreach (@items)
  {
      if (-l $_)    ## this is what I don't understand: the meaning of -l
      {
          ...
      }
  }
  </code></pre>
  
  <p>Thanks for any help.</p>