use Time::HiRes qw(gettimeofday);
use POSIX qw(strftime);

my $ArchiveDir = "/tmp/archive/";

( -w $ArchiveDir ) or die "archive dir $ArchiveDir not writable";

# Get the number of microseconds.
(undef, $usec) = gettimeofday;

# Now create the archive filename and open that file.  Use
# sub-second resolution for name to make sure it's unique.
$ArchiveFile = strftime "%Y%m%d%H%M%S", localtime;
# make sure we get the full 6 digits on microseconds.
$ArchiveFile .= "." . sprintf("%06d",$usec);

# Combine $ArchiveDir with the filename.
$ArchiveFile = $ArchiveDir . $ArchiveFile;

# open the file.
open(ArchiveFH,">$ArchiveFile") or 
  die "failed to open ArchiveFile: $!";