Hi @Allen_Roy,
This would mean that you have a subject named sub-1 in your BIDS directory, and want to limit fMRIPrep to 4 CPUs. Just making sure that that is is the case?
--mem in the fMRIPrep command line is defined in megabytes, and I imagine you wanted this to be 6 gigabytes instead of megabytes. So, you can re-add the mem_mb variable similar to what you had before so you have a gigabytes number for the docker memory argument, and a megabytes number for the fmriprep argument.
Again, you should use $wkd for the -w argument instead of $HOME.
This flag is not recommended (see here)
fMRIPrep will make its own subject specific folders in the output directory. By convention, most people will define the output directory as $BIDS/derivatives/, which in your case is $HOME/fmriprepdemo_lang-prod/derivatives/.
Best,
Steven
