svoid copyAllFilesInDirectory_rec_noOverwrite(File src, File dest) ctex {
  print("Listing " + f2s(src));
  for (File f : listFiles(src)) {
    print("Copying " + f2s(f));
    File destFile = newFile(dest, f.getName());
    if (fileExists(destFile))
      fail("Won't overwrite " + f2s(destFile) + " with contents of " + f2s(f));
    if (isSymLink(f))
      Files.createLink(fileToPath(destFile), fileToPath(f).toRealPath());
    else if (isFile(f))
      copyFile(f, destFile);
    else if (isDirectory(f)) {
      mkdirs(destFile);
      copyAllFilesInDirectory_rec_noOverwrite(f, newFile(dest, f.getName()));
    }
  }
}