title: Use of uninitialized value in concatenation (.) or string at mksmksmks.pl line 63
body: <p>I have written some code, and I am not sure what the error is. I am getting the error:</p>
  
  <blockquote>
    <p>Use of uninitialized value in concatenation (.) or string at mksmksmks.pl line 63</p>
  </blockquote>
  
  <p>My code is as follows:</p>
  
  <pre><code>for(my $j = 0; $j &lt; $num2; $j++) {
    print {$out} "$destination[$j]|$IP_one_1[$j]|$IP_one_2[$j]|$reached[$j]|$IP_two_1[$j]|$IP_two_2[$j]\n";`
  }
  </code></pre>