como escribir automaticamente la contraseña solicitada por un programa linux

#include <unistd.h>
#include <termios.h>
#include <iostream>

using namespace std;

int main() {
    cout << "Enter password: " << flush;
    struct termios settings;
    tcgetattr(STDIN_FILENO, &settings);
    settings.c_lflag =  (settings.c_lflag & ~(ECHO));
    tcsetattr(STDIN_FILENO, TCSANOW, &settings);

    string password;
    cin >> password;

    settings.c_lflag = (settings.c_lflag |   ECHO );
    tcsetattr(STDIN_FILENO, TCSANOW, &settings);
    cout << endl << "Password is " << password << endl;
}