Here's a simple example using Date::Calc that will print out a list of dates from today to 31 days in the past.

#!/bin/perl

use warnings;
use strict;

use Date::Calc qw( Delta_Days Add_Delta_Days Date_to_Text Today);

#create an infinite loop, probably not what you really want!
while(1)
{
        #get today's date
        my @today = Today();
        my $i = 31; #how many days do you want to go back?
        my @datelist; #the list of dates

        #create the list of dates
        while ($i-- > 0 )
        {
                #subtract $i days from today's date
                my @date = Add_Delta_Days(@today, -$i);

                # [ @date ] creates an array ref
                push (@datelist, [ @date ]);
        }

        #datelist is now an array of array refs (in the Date::Calc for
+mat)

        #print out the list
        foreach my $date (@datelist)
        {
                #since @datelist is really an array of array refs,
                #we dereference it using: @{$date}
                print Date_to_Text(@{$date}),"\n";
        }

        #sleep for a day (1 day = 86400 seconds)
        sleep(86400);
}
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PS. -- since you're new here, I highly recommend taking a look at turnstep's guide to the monastery.