3 set -- 1 2 3 4 5 6 7 8 9 10 11 12 13
4 [ "$#" = 13 ] || echo '$# wrong'
5 [ "${#}" = 13 ] || echo '${#} wrong'
6 [ "${##}" = 2 ] || echo '${##} wrong'
8 [ "$#" = 0 ] || echo '$# wrong'
9 [ "${#}" = 0 ] || echo '${#} wrong'
10 [ "${##}" = 1 ] || echo '${##} wrong'