It can be done with two commands…
To put the view mode into buffer visualization mode, use the following: ViewMode VisualizeBuffer
To specify which buffer to visualize, use: r.BufferVisualizationTarget ...
Where the list of target names are:
BaseColor
CustomDepth
CustomStencil
FinalImage
ShadingModel
MaterialAO
Metallic
Opacity
Roughness
SceneColor
SceneDepth
SeparateTranslucencyRGB
SeparateTranslucencyA
Specular
SubsurfaceColor
WorldNormal
AmbientOcclusion
CustomDepthWorldUnits
SceneDepthWorldUnits
PreTonemapHDRColor
PostTonemapHDRColor