This works on my machine. No guarantees about it working anywhere else...

use v5.12;
use POSIX;

my $termios = POSIX::Termios->new(\*STDIN);
$termios->getattr;
my $lflag = $termios->getlflag;
$termios->setlflag($lflag & ~(&POSIX::ICANON) );
$termios->setattr;

my $pwd;
while (my $c = getc STDIN)
{
    last if $c eq "\n";
    print "\r \r";
    $pwd .= $c;
}

$termios->setlflag($lflag);
$termios->setattr;

warn "GOT: $pwd\n";
[download]