If your CLI script accepts input from STDIN and you also want it to prompt for a password (e.g. as mysql client does), then readline() won't work for you.
What you need to do is read from the terminal device as shown below.
function readline_terminal($prompt = '') {
$prompt && print $prompt;
$terminal_device = '/dev/tty';
$h = fopen($terminal_device, 'r');
if ($h === false) {
#throw new RuntimeException("Failed to open terminal device $terminal_device");
return false; # probably not running in a terminal.
}
$line = rtrim(fgets($h),"\r\n");
fclose($h);
return $line;
}
$pass = readline_terminal('Password: ');