I would use in programmatic way chimera to elaborate a molmap of a peptide bound in a receptor. 

I'm able to load the pdb and elaborate the molmap of the peptide

"/home/guido/.local/UCSF-Chimera64-1.16/bin/chimera --nogui load <NAMEFILE>

molmap :.P 5;"

Now I would save the molmap of the peptide to do a fitmap vs another peptide.

I tried 

save test.mrc

but the following msg is prompted to me 

Volume data sets

molmap <namefile>.pdb res 5

were not saved in the session.  To have them included
in the session they must be saved in separate volume
files before the session is saved.

DO you have any tips?

Thank you 

Guido