use Net::Telnet;
 
my $telnet3;
$telnet3 = new Net::Telnet(timeout => 10,
                Errmode => 'die');
 
$telnet3->open('ip_address'); 
$telnet3->login('username', 'password');
@lines = $telnet3->cmd("who");
 
 
open(FILE, ">file.txt");
 
    print FILE ("@lines\n");

print("logged in to the device.\n");