title: What is the significance of an underscore in Perl ($_, @_)?
body: <p>I am new to Perl, and I used them like this</p>
  
  <p><code>$_</code></p>
  
  <pre><code>foreach (@list) {
      print "$_\n";
  }
  </code></pre>
  
  <p><code>@_</code></p>
  
  <pre><code>sub search {
      my ($no, @list) = @_;
  }
  </code></pre>
  
  <p>How exactly do these underscore variables work in Perl? What are the other constructs where they are useful?</p>