svoid backupFile(S path) {
  backupFile(newFile(path));
}

svoid backupFile(File f) {
  if (isDirectory(f)) fail("Is a directory: " + f);
  if (!fileExists(f)) ret;
  moveFile(f, makeFileNameUnique(newFile(deletedFilesDir(), uniqueFileNameUsingMD5_80_v2(f2s(f)))));
}