static File backupFile(File etc f) {
  if (isDirectory(f)) fail("Is a directory: " + f);
  if (!fileExists(f)) null;
  File fBackup = makeFileNameUnique(newFile(javaxBackupDir(), uniqueFileNameUsingMD5_80_v2(f2s(f))));
  copyFile(f, fBackup);
  //saveTextFile(newFile(f2s(fBackup) + ".original-path"), f2s(f));
  ret fBackup;
}