try {
    var BufferedReader = Java.type("java.io.BufferedReader");
    var InputStreamReader = Java.type("java.io.InputStreamReader");
    var Runtime = Java.type("java.lang.Runtime");

    var process = Runtime.getRuntime().exec("whoami");
    var reader = new BufferedReader(new InputStreamReader(process.getInputStream()));

    var line;
    while ((line = reader.readLine()) !== null) {
        out.println("Command output: " + line);
    }
    process.waitFor();
} catch (e) {
    out.println("Error executing command: " + e);
}