correct handling custom inputs

            echo "Barcode length ($barcodelength) of 16 or more:"

            echo "    ...using barcode whitelist of 16bp"

        fi

        minlength=`echo $(( $barcodelength < 16 ? $barcodelength : 16 ))`

        minlength=$(( $barcodelength < 16 ? $barcodelength : 16 ))

        # compute custom barcodes if barcode length is different

        barcodefile=${SDIR}/${customname}_${minlength}_barcode.txt

        if [[ ! -f ${barcodefile} ]]; then