Is there a way to utilize the =now() of =today() functions to update each day
without having to open the workbook?

I am using Excel to house a list of products and associated data for use in
a barcode label sofware program and I would like the date to be printed on
the label each time it is executed. Typically this would not be an issue (as
the barcode software has date functions included) but I am not able to format
the date value as a julian date, so I am using an Excel formula to convert
it. I need the date to change each day without opening the workbook to
eliminate any potential overwriting of the contents and also to eliminate an
unnecessary step in the labeling process.