void() { echo "VOID: $1"; exit 2; }
trial() {
  local arm="$1" n="$2" id="$arm-$n"
  echo "OK id=[$id] outf=[R/$id.out]"
}
for n in 1 2 3; do trial a "$n"; done
for n in 1 2 3; do trial b "$n"; done