static void backupAndCleanProgramDir(S progID) {
  progID = formatSnippetID(progID);
  File dir = getProgramDir(progID);
  if (!dir.exists()) return;
  File backupDir;
  long date;
  do {
    date = now();
    backupDir = new File(userHome(), "JavaX-Backup/" + progID + "/" + date);
  } while (backupDir.exists());
  
  mkdirsForFile(backupDir);
  dir.renameTo(backupDir);
  print("Moved " + dir.getAbsolutePath() + " to " + backupDir.getAbsolutePath());
}