I'm actually not sure that you need this concept at all. If you just need the last data for each backup set, then I would process the input file, replacing old info with new as it becomes available. Then the output becomes "hey here is the most recent stuff I have". All of this processing will be so fast that there is no need to keep track of what you did before, just do it all again to keep things simple. I mean there are 86,400 seconds in a day and running a program once per day that takes one second is nothing in the scheme of things!

The problem I came into was that the data for each backup set doesn't appear to be "symmetric". In other words, sometimes some parm values are "missing". This can cause some previous value to continue to be "carried forward" when that is not the right thing to do.

Rather than getting into some "spec war", I post a simple minded use of my previously posted code to report "last values" of each set and then you can tell me: "Hey this would have been right if it had of done X". Below I didn't use $date, don't know why you need $date.

In doing this short thing, I noticed that $param could have a leading space, so I changed a regex.

use strict;
use Data::Dumper;

my %backups;

while (<DATA>)
{
   next if (/^\s*$/);    #skip blank lines
   chomp;
   
   my ($date, $backupset , $parm , $value) = parseline($_);
   
   if ($value)
   {
      $backups{$backupset}{$parm} = $value;
   }   
}

print Dumper \%backups;

sub parseline
{
   my $line = shift;
   my ($date, $rest) = $line =~ m/(^.*\d{4}):(.*)/;
   my ($backupset,  $msg) = split(/backup:INFO:/, $rest);
   $backupset =~ s/:\s*$//;  #trim some unwanted thing like ':' is ok
   $backupset =~ s/^\s*backup\.//; #more than one step is just fine!
   my ($parm, $value) = $msg =~ m/\s*(.*)=\s*(.*)\s*/;

   $parm  ||= $msg;   #if match doesn't happen these will be undef
   $value ||="";      #this trick makes sure that they are defined.

   return ($date, $backupset, $parm, $value);
}   

=print
#some reformatting to try to stop line wrap....
$VAR1 = {
          'set1_lvm' => {
 'backup-size' => '187.24 GB',
 'backup-set' => 'backup.set1_lvm',
 'backup-time' => '01:59:04',
 'backup-date-epoch' => '1281942003',
 'backup-status' => 'Backup succeeded',
 'last-backup' => '/home/backups/backup.set1_lvm/20100815000006',
 'backup-type' => 'regular',
 'backup-date' => '20100816000003'
                        },
          'set2_lvm_lvm' => {
  'backup-size' => '424.53 GB',
  'backup-time' => '04:33:12',
  'backup-status' => 'Backup succeeded',
  'last-backup' => '/home/backups/backup.set2_lvm_lvm/20100814200003'
                            },
          'set2_lvm' => {
  'backup-directory' => '/home/backups/backup.set2_lvm/20100815200003'
+,
  'backup-set' => 'backup.set2_lvm',
  'backup-date-epoch' => '1281927603',
  'backup-type' => 'regular',
  'backup-date' => '20100815200003'
                        }
        };
=cut
__DATA__
Sun Aug 15 20:00:03 2010: backup.set2_lvm:backup:INFO: START OF BACKUP
Sun Aug 15 20:00:04 2010: backup.set2_lvm:backup:INFO: backup-set=back
+up.set2_lvm
Sun Aug 15 20:00:04 2010: backup.set2_lvm:backup:INFO: backup-date=201
+00815200003
.....
use __DATA__ segment from my previous post
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