test.php

<?php

$stdin = fopen('php://stdin', 'r');
while (true) {
    $input = fgets($stdin);
    if ($input == false) {
        echo "php EOF!\n";
        break;
    }

    echo "php: " . $input;
    if ($input === "ffmpeg dunzo\n") {
        echo "php dunzo!\n";
        break;
    }
}