Printing expect output without calling the variable

Question

I'm trying to understand the Expect Perl module.

I want to take the value and the machine from $var, but I couldn't make my code work even if I used regular expressions.

I want to take from $var the machine and the value from the command prompt (like machine 1 - 7) but I don't know why it prints $var in the terminal as I didn't call the $var variable

$Expect::Exp_Internal =0;
my $admin_user = "root";
my $timeout = 40;
my $prompt = '~]#';


my @devices =qw(
machine1
machine2
machine3);


foreach my $device (@devices){
my $exp = Expect->spawn("ssh", "-o", "UserKnownHostsFile /dev/null", "root\@$device");

$exp->log_user(0);


my $seen_user = 0;


$exp->expect(
    $timeout,
    [
        qr/connecting \(yes\/no\)\? / => sub {
            my $self = shift;
            $self->send("yes\r");
            exp_continue;
        }
    ],
    [
        qr/User: ?/ => sub {
            my $self = shift;
            if ( $seen_user == 1 ) {
                $var .= "Bad password on $device \n<br>";
                $exp->soft_close();
            }
            #  $self->send("$admin_user\n<br>");
            $seen_user = 1;
            exp_continue;
        }
    ],
    [
        qr/$prompt/ => sub {
            my $self = shift;
            #    print 'first_prompt';
        }
    ],
    [
        'timeout' => sub {
            $var .= "timed out during login on $device\n<br>";
        }
    ]
);

$exp->log_user(1);

# This following line is printed, without being called:

my $var = $exp->send("ps -aef | grep -i app | wc -l\n");

#$var =~ s/\D+//g;
#print 'numbers'.$var;

print $var;
undef $var;

my $logout_sent = 0;

$exp->expect(
    $timeout,
    [
        qr/$prompt/ => sub {
            my $self = shift;
            $exp->log_user(0);
            # $self->send("ps -aef | grep -i sql | wc -l\r");
            $self->send("logout\r");
            $logout_sent = 1;
            exp_continue;
        }
    ],

    }],

    [
        qr/\(y\/N\)/ => sub {
            my $self = shift;
            $self->send("y");
            print "ok\n<br>";
            #    exit 0;
        }
    ],
    [
        'timeout' => sub {
            print "timed out waiting for prompt\n<br>";
            # exit 1;
        }
    ],
    [
        'eof' => sub {
            if ($logout_sent) {
                $var .= "succesfully logged out from the $device\n<br>";
                #exit 0;
            }
            else {
                $var .="unexpected eof waiting for prompt on $device\n<br>";
            }
        }
    ]
);

}

The Output

<br>ps -aef | grep -i app | wc -l
7
[root@machine1 ~]# succesfully logged out from the machine1
<br>ps -aef | grep -i app | wc -l
9
[root@machine2 ~]# succesfully logged out from the machine2
<br>ps -aef | grep -i app | wc -l
7
[root@machine3 ~]# succesfully logged out from the machine3

Answer 1

You can get the value of the machine like this:

# $exp->clear_accum(); # clear the accumulator if you need to
$exp->expect( $timeout, '-re', 'root@machine\d+');
my ($machine_number) = $exp->match() =~ /root@machine(\d+)/;

Then you can get the number of processes like this:

$exp->clear_accum(); # clear the accumulator if you need to
$exp->send("ps -aef | grep -i app | wc -l\n");
$exp->expect( $timeout, '-re', '^\d+');
my ($num_processes) = $exp->match() =~ /(\d+)/;