Thanks for your comment on that template chaley.
I guess I should note here that the template in that other thread (for purposes of defining a user-created column that is a combination of the information in other columns) is:
Code:
{last_modified:'days_between($, select(formats_modtimes('iso'), 'EPUB'))'}
[/QUOTE]
but the numeric value that was produced in my Calibre column today for all my books was the number of days between when the ePub file was last changed and today's date.
The problem seems to be that when I added a user-created column today to test out that template (or whenever I add any temporary column for special sorts or whatever), it results in changing the "metadata modification date" for
all my ePubs.
The primary metadata changes that I would mainly care about for rerunning Modify ePub on previous books would be changes to standard non-user-created metadata fields (e.g. author, title, series, index, comments) and the book cover.
But I guess there is no way to distinguish the dates for changes to one or more of those fields, from an overall "metadata modification date" that would change for all books when any user-created column is added, modified or deleted.
That template may be the best thing available, but depending on how an individual works with the various data fields, I guess the template may not be able to provide the information needed to determine with hindsight which ePubs warrant a re-run of the plugin Modify ePub?