use DateTime;
my $dt = DateTime->now;
my $file = 'foo_' . $dt;
print $file;

##</code><code>##

foo_2015-08-06T17:05:17

##</code><code>##

$dt = DateTime->now( time_zone => 'local' );

##</code><code>##

my $dt = DateTime->now(time_zone => 'local')->strftime("%Y-%m-%d-%k-%M-%S");

##</code><code>##

2015-08-06-10-42-18