I have two OBJ files, which contain a mesh that describes the same shape. One has ~10k vertices, and has texture coordinates. The other has ~5k vertices, and doesn't have texture coordinates.

How do I transfer the texture coordinates to the second mesh quickly, without having to unwrap the texture again?

Preferrably I'd use some open source software like Blender or a dedicated script. But if there is an easy solution with proprietary software I'll find a way to access that.