System.err.println("Usage: java CheckWrapper.java < commits.txt");
            System.exit(2);
        }

        try {
            checkCommitsFromStdin();
        } finally {
            THREAD_POOL.shutdown();
        }
    }

    private static void checkCommitsFromStdin() throws IOException, InterruptedException, ExecutionException {
        String originalHead = stdout("git", "rev-parse", "HEAD").trim();