/** writes safely (to temp file, then rename) */
static File saveLinesAsTextFile(String fileName, Iterable<S> lines) ctex {
  ret saveTextFile(fileName, lines(lines));
}

static File saveLinesAsTextFile(File fileName, Iterable<S> lines) {
  ret saveLinesAsTextFile(fileName.getPath(), lines);
}

Began life as a copy of #1001042