or download this
my @TimeArray = localtime(time);
my $year = sprintf ("%04d",$TimeArray[5]+1900);
...
my $hour = sprintf ("%02d",$TimeArray[2]);
my $minute = sprintf ("%02d",$TimeArray[1]);
my $datestamp = "$year"."_"."$monthasnum"."_"."$day"."_"."$hour" ."_"
+."$minute" ;