// returns "naked" ids (without the #)
// might return ids more than once
static L<S> programsRunningInAllVMs() {
  L<S> answers = sendToAllVMs("which programs are you running (ids only)");
  new L<S> l;
  for (S s : answers) {
    new Matches m;
    if (match3("these: *", s, m))
      l.addAll((L) unstructure(unquote(m.m[0])));
  }
  ret l;
}