d.colormode and r.mapmask

[IBH7CAB at MVS.OAC.UCLA.EDU]

Now that I finally have a DEM, satellite imagery and ground truth
data for my study area, I have (enjoyed) the opportunity to
try out some of the really nice features in GRASS that were
previously impossible.  I do have a couple of questions related to
image classification:

1)  I can't seem to slide colors while running d.colors.  I have set
    d.colormode mode=float beforehand, but no pixels change colors
    once I am actually in d.colors.  I am running GRASS4.0 on a
    SPARCstation1 under OPENWINDOWS.  I should mention that I am
    able to slide colors if I select SUNVIEW as my GUI.  Has anyone
    else reported this problem?

2)  What happended to mapmask?  I was reading the 4.0 manual entry
    on r.mask, and it refers to r.mapmask.  Yet, r.mapmask is not
    listed as a command in the manual.  Nor is the command found if
    I enter it at the GRASS 4.0 prompt.  I need to make a number of
    circular-shaped binary masks for my analysis.  Is there another way
    to accomplish this?

Thanks in advance for your help!