to find the installed CudNN version code example
Example: check cuda nn version
cat /usr/local/cuda/include/cudnn.h | grep CUDNN_MAJOR -A 2orcat /usr/include/cudnn.h | grep CUDNN_MAJOR -A 2
cat /usr/local/cuda/include/cudnn.h | grep CUDNN_MAJOR -A 2orcat /usr/include/cudnn.h | grep CUDNN_MAJOR -A 2