use Device::SerialPort;
use Data::Dump qw(dump);
-my $device = $ENV{DEVICE} || '/dev/ttyUSB0';
+my $device = $ENV{DEVICE} || shift @ARGV || '/dev/ttyUSB0';
my $port = Device::SerialPort->new( $device ) || die "$device: $!";
$port->baudrate(115200) || die "fail $device baudrate";