See this
$ docker run -d busybox top
$docker ps -a
CONTAINER ID     IMAGE      COMMAND     CREATED        STATUS        PORTS    NAMES
3eca7c034b21     busybox    "top"       6 seconds ago  Up 5 seconds           recursing_dirac
Look at the command. It says top. That's because it was passed to the busybox container and shows up in docker ps -a.