afni.nimh.nih.gov

This is probably a very simple thing, but I can't figure it out.

If I have a 3d data file with integer values only, how can I obtain a list of unique voxel values in the file or in a subbrick? For example, doing this to the standard segmentation produced by @animal_warper should output something like
0
1
2
3
4

If there was a way to extract any labels associated with the ROIs, that would be great too.
E.g.
0
1 CSF
2 GM
3 scGM
4 WM