### start of code where I capture the command output
    $exp->send("show port\n");
    $exp->expect(15,
    [ '# ', sub { my $self = shift;
        @port = $self->exp_before; }],
    );

   foreach my $line (@port) {
      my @PORTS = split('\n', $line);
        foreach my $str (@PORTS){
          if ($str =~ /^\d/) {
             $PORT_NO = (split /\s+/, $str) [0];
             $exp->send("show port $PORT_NO detail\n");
             $exp->expect(15,
             [ '# ', sub { my $self = shift;
### Here I use a string to cature the output
             $output_str = $self->exp_before; }],
            );
               foreach my $string (split('\n', $output_str)){
                  chomp $string;
                  if ($string =~ /Part Number/) {
                      $model = (split /\s+/, $string) [3];
                      print "Node: $NODE_NAME,Port: $PORT_NO,Part: $model\n";
                  }

               }
          }
        }
    }