With NVIDIA drivers installs there is the nvidia-smi tool. See the following link for info:
https://developer.nvidia.com/nvidia-system-management-interface
See this link for the man page and various switches/tools to use:
http://developer.download.nvidia.com/compute/cuda/5_5/rel/nvml/nvidia-smi.5.319.43.pdf
For GRID specifically, keep in mind the location of the driver. As an example, if using vSGA (shared) in VMware then the driver is the VIB loaded on the ESXi hypervisor, so the nvidia-smi executable is located there, on the hypervisor. If on that same deployment you chose to use on GPU as pass-through then that GPU is looking to the NVIDIA driver on the guest and so nvidia-smi is located on the guest.