($month, $year) = (localtime)[4..5];
# convert from index to 'normal'
$this_months_year = $year + 1900;
$last_months_year = $this_months_year;
$this_month = $month + 1;
# fix month if = 0
$last_month = $month;
$last_month or $last_month = 12;
# roll back year if this month is january
($this_month == 1) and $last_months_year--;
$this = sprintf("%04d%02d", $this_months_year, $this_month);
$last = sprintf("%04d%02d", $last_months_year, $last_month);

@files_this = <companyname.com-$this??_log>;
@files_last = <companyname.com-$last??_log>;