activate_cuda.sh

function activate_cuda(){
    if [ $# -ne 1 ] ; then
        echo "Usage: active_cuda <version>"
        echo "       i.e. activate_cuda 8.0"
    else
        CUDA_VER=$1
        CUDA_SRC="/usr/local/cuda-$CUDA_VER"
        CUDA_DST="/usr/local/cuda"
        if [ -d "$CUDA_SRC" ]; then
            echo "Activating CUDA $CUDA_VER intalled at $CUDA_SRC"
            if [ -L "$CUDA_DST" ]; then
                # Dst is a symbollic link which exists - update
                sudo ln -sfn $CUDA_SRC $CUDA_DST
            else 
                if [ ! -e "$CUDA_DST" ]; then
                    # If dst does not exist, create the symlink.
                    sudo ln -s $CUDA_SRC $CUDA_DST
                else
                    # File exists and is not a symlink. error.
                    echo "Error: $CUDA_DST exists but is not a symlink."
                    echo "      Aborting."
                    return
                fi
            fi
        else
            echo "Error: CUDA Version $CUDA_VER is not installed at $CUDA_SRC"
            echo "       Using existing cuda version"
        fi

        echo ""

        # Get the cuda version and output.
        NVCC_MAJOR=$(nvcc --version | sed -n -r 's/.*(V([0-9]+).([0-9]+).([0-9]+))/\2/p')
        NVCC_MINOR=$(nvcc --version | sed -n -r 's/.*(V([0-9]+).([0-9]+).([0-9]+))/\3/p')
        NVCC_PATCH=$(nvcc --version | sed -n -r 's/.*(V([0-9]+).([0-9]+).([0-9]+))/\4/p')
        echo "Current CUDA Version: $NVCC_MAJOR.$NVCC_MINOR.$NVCC_PATCH"
    fi
}