Thanks MillerH!
This is what I ended up with:
#!/usr/bin/perl -w
use Date::Calc qw(Days_in_Month System_Clock Add_Delta_YM);
my ($year,$month,$day, $hour,$min,$sec, $doy,$dow,$dst) = System_Clock([$mgt]);
my ($ReportYear,$ReportMonth,$ReportDay) = Add_Delta_YM($year,$month,$day, 0, -1);
my...