/usr/bin/cleanipcs.mpich-shmem is in mpich-shmem-bin 1.2.7-10ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/bin/../lib/mpich-shmem/sbin/cleanipcs
/usr/bin/../lib/mpich-shmem/sbin/cleanipcs