Problem with date...

[Xpression]

        Hi all, I'm logging certain types of files to a daily grouping with
the following format `date +%v` and the output format for today is eg.
29-Oct-2003, it's fine but this happens at 12:00 pm at night to rotate
everyday, and I want to check and edit some lines on the file that was
recorded but date is the actual and date +%v return me the date of today and
not of yesterday, is there a way to recognize the past file ???