Should say
leftVolFile="$resultsDirectory/$subjectName/mri/lh.${suffix}Volumes-${prefix}.v20.txt"
rightVolFile="$resultsDirectory/$subjectName/mri/rh.${suffix}Volumes-${prefix}.v20.txt"
because as specified "T1" is the ${prefix} which is how the subfields file names end. Obviously, can flip suffix and prefix throughout so it is more intuitive. Seems to work fine after this adjustment.
Josh
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Joshua C. Gray, PhDPsychology Instructor
Center for Deployment Psychology