use IPC::Run qw(start pump finish);

my @args;
push @args, $app_path;
my ($in, $out, $err);

# starting the application
my $handle = start \@args, \$in, \$out, \$err;

# wait until prompted for input
pump $handle until $out =~ /Login:/;
$in .= "Boris\n";

# wait until prompted for password
pump $handle until $out =~ /Password:/;

# and so on ...

##</code><code>##

$client_descr->{"Handle"} = $handle;
$client_descr->{"In"} = $in;
$client_descr->{"Out"} = $out;
$client_descr->{"Err"} = $err;

##</code><code>##

my ($handle, $in, $out) = ($client_descr->{"Handle"}, $client_descr->{"In"}, $client_descr->{"Out"});

##</code><code>##

$in .= "new data\n";
pump $handle until $out =~ /data arrived:/;
print $out;