I need to express $\nabla = (\partial_x,\partial_y,\partial_z)$ as a vector, so that I can compute the differential operator given by $A\cdot\nabla$ (where here $A$ is a 3x3 matrix) using Mathematica. Subsequently, I need to be able to do operations with $\nabla_A := A \cdot \nabla$ on a vector/scalar and get the differential operator applied to the vector/scalar (e.g. either $\nabla_A\cdot \vec{v}$ or $\nabla_A \vec{v}$ or $\nabla_A \sigma$, where $\vec{v} \in \mathbb{R}^3$ and $\sigma \in \mathbb{R}$).
This comes down to treating $\nabla$ as a vector, which isn't allowed (as far as I can tell) by the Grad[-] function in Mathematica.
After browsing the documentation and forums, I couldn't figure out an easy way to try to do this. I am new to Mathematica, so any help is greatly appreciated!