static Map<Int, S> psPidsAndCommands() {
  if (isWindows()) fail("Unix only");
  S psOutput = backtick("ps -aef");
  L<S> lines = toLines(psOutput);
  S header = lines.get(0);
  L<S> body = dropFirst(lines);
  final int i1 = header.indexOf(" PID");
  final int i2 = header.indexOf("CMD");
  ret pairsToTreeMap(map(func(S s) -> Pair<Int, S> {
    pair(parseInt(trim(substring(s, i1-2, i1+4))), substring(s, i2).trim())
  }, body));
}