tie (my %hash, 'DB_File', $file, O_RDWR, 0600) || next;
    foreach my $key ( keys %hash ) {

        if (!defined $hash{$key}) {
[download]

The undef value is an internal perl meta-value.    When you store data on an external device (like a tied hash) the undef value is converted to a string, so trying to use defined on this value makes no sense.

Hi,

Thanks everyone for your offer to help. I've posted below a complete program that runs on my system. Where it encounters an error and quits, it displays the following, with a few of the preceding lines:

bucket: aa      type: spam      2012-07-02      20120702T132446
bucket: aa      type: spam      2012-07-07      20120707T083754
bucket: aa      type: spam      2012-07-02      20120702T203543
bucket: aa      type: virus     2012-07-08      20120708T113543
bucket: aa      type: spam      2012-07-16      20120716T151849
bucket: aa      type: virus     2012-07-22      20120722T100147
bucket: aa      type: spam      2012-07-03      20120703T042249
bucket: aa      type: spam      2012-07-07      20120707T204829
Use of uninitialized value in split at ./list_hash.pl line 32.
Use of uninitialized value $dt in pattern match (m//) at ./list_hash.p
+l line 35.
key 2 not defined. Deleting.
[download]

It's reading from 255 hashes for each host, which you aren't going to have, so it probably won't execute for you.

As I mentioned previously, the delete() isn't actually deleting for some reason. If I run the program again, it dies at the same spot, indicating to me that the record with the undef'd value or key still remained.

Any ideas greatly appreciated.

#!/usr/bin/perl -w

  # use perl;
  use DB_File;
  use DBI;
  use File::Basename    qw(basename);
  use strict;
  use vars              qw($verbose);

  my $me    = basename($0); $me =~ s/\.pl$//;
  $verbose    = shift || 1; 

  sub DBG($);

  my $qdir        = '/var/www/noc.mydomain.com-80/';
  my %hashes        = ( );

  my $version        = '1.9';
  my @mailhosts        = qw();

  push @mailhosts, 'mail01';
  push @mailhosts, 'mail02';

  foreach my $mhosts (@mailhosts) {
  for (my $i = 0; $i < 256; $i++) {
    my $bucket    = sprintf('%02x', $i);
    my $file    = sprintf('%s/%s/%02x.db', $qdir, $mhosts, $i);

    tie (my %hash, 'DB_File', $file, O_RDWR, 0600, $DB_HASH) || next;
    foreach my $key ( keys %hash ) {

       my @tmp         = split /\t/, $hash{$key}, 7;
       my $type      = $tmp[0];
       my $dt        = $tmp[1];
       my ($year, $month, $day) = $dt =~ m|(\d{4})(\d{2})(\d{2})T.*|;
       if(!defined($year)) { DBG("key 2 not defined. Deleting.\n"); de
+lete($hash{$key}); untie %hash; exit 1; };
       if(!defined($month)) { DBG("key 3 not. Deleting.\n"); delete($h
+ash{$key}); untie %hash; exit 1; };
       if(!defined($day)) { DBG("key 4 not defined. Deleting.\n"); del
+ete($hash{$key}); untie %hash; exit 1; };
       printf("bucket: %s\ttype: %s\t%s-%s-%s\t%s\n",$bucket,$type,$ye
+ar,$month,$day,$dt)    

    }
    untie %hash;
  }
} # end foreach mailhost

sub DBG($) { my $msg = shift; print $msg if ($verbose); }
[download]

Version with line numbers:

     1    #!/usr/bin/perl -w
     2    
     3      # use perl;
     4      use DB_File;
     5      use DBI;
     6      use File::Basename    qw(basename);
     7      use strict;
     8      use vars              qw($verbose);
     9    
    10      my $me    = basename($0); $me =~ s/\.pl$//;
    11      $verbose    = shift || 1; 
    12    
    13      sub DBG($);
    14    
    15      my $qdir        = '/var/www/noc.mydomain.com-80/';
    16      my %hashes        = ( );
    17    
    18      my $version        = '1.9';
    19      my @mailhosts        = qw();
    20    
    21      push @mailhosts, 'mail01';
    22      push @mailhosts, 'mail02';
    23    
    24      foreach my $mhosts (@mailhosts) {
    25      for (my $i = 0; $i < 256; $i++) {
    26        my $bucket    = sprintf('%02x', $i);
    27        my $file    = sprintf('%s/%s/%02x.db', $qdir, $mhosts, $
+i);
    28    
    29        tie (my %hash, 'DB_File', $file, O_RDWR, 0600, $DB_HASH)
+ || next;
    30        foreach my $key ( keys %hash ) {
    31    
    32           my @tmp         = split /\t/, $hash{$key}, 7;
    33           my $type      = $tmp[0];
    34           my $dt        = $tmp[1];
    35           my ($year, $month, $day) = $dt =~ m|(\d{4})(\d{2})(\d
+{2})T.*|;
    36           if(!defined($year)) { DBG("key 2 not defined. Deletin
+g.\n"); delete($hash{$key}); untie %hash; exit 1; };
    37           if(!defined($month)) { DBG("key 3 not. Deleting.\n");
+ delete($hash{$key}); untie %hash; exit 1; };
    38           if(!defined($day)) { DBG("key 4 not defined. Deleting
+.\n"); delete($hash{$key}); untie %hash; exit 1; };
    39           printf("bucket: %s\ttype: %s\t%s-%s-%s\t%s\n",$bucket
+,$type,$year,$month,$day,$dt)    
    40    
    41        }
    42        untie %hash;
    43      }
    44    } # end foreach mailhost
    45    
    46    sub DBG($) { my $msg = shift; print $msg if ($verbose); }
    47
[download]

Instead of this:

 foreach my $key ( keys %hash ) {

    my @tmp = split /\t/, $hash{$key}, 7;
    my $type = $tmp[0];
    my $dt   = $tmp[1];
    my ($year, $month, $day) = $dt =~ m|(\d{4})(\d{2})(\d
+{2})T.*|;
[download]

Try this and see what you get:

• Remove the LIMIT in the split function, in this case 7, and change "\t" to "\s+"
• Test your match string, i.e $dt if it matches

 foreach my $key ( keys %hash ) {

    my @tmp = split /\s+/, $hash{$key};
    my $type = $tmp[0];
    my $dt   = $tmp[1];
    my ($year, $month, $day) = ('','','');
    if($dt =~ m|(\d{4})(\d{2})(\d+{2})T.*$|){
      ($year, $month, $day)=($1,$2,$3);
    }
    ......
    ......
printf("bucket: %s\ttype: %s\t%s-%s-%s\t%s\n",$bucket
+,$type,$year,$month,$day,$dt);
......
[download]

The problem is that the delete($hash{$key}) doesn't seem to actually be deleting the hash

How do you delete undefined hash key?
if hash key is not present, there is nothing to delete. Don't you think so?
Peruse this:

use Data::Dumper;

  my $family={ father=>'foo', mother=>'bar',};

       for(keys %$family){
            if(!defined($_)){
                delete $family->{$_}
             }
        }

   print Dumper $family; # print out your hash
[download]

use Data::Dumper;

  my $family={ father=>'foo', mother=>'bar',};

       for(keys %$family){
            if(defined($_)){
                delete $family->{$_}
             }
        }

   print Dumper $family; # print empty hash
[download]

UPDATE:
Also in this:

my $file    = sprintf('%s/%s/%02x.db', $qdir, $mypc, $i);
[download]

It just seemed like there was _something_ in that position in the database for it to return the undefined value.

I thought the issue was that split was being run against a string with null values among the tab delimiter or the entry was somehow otherwise incomplete, leading to the "Use of uninitialized value in split at ./list_hash.pl line 74." that I receive if I remove the prior checks and try and split the string anyway.

It loks like you've used all different constructs, and I'm not familar with the abstraction your using. It's beyond my level of perl understanding, unfortunately.

Thanks,
Alex

If then you suspect split function, then check what you are getting for each split "action" ( using print ), before assigning them to other variables. like so:

 print join "\n",split /\t/, $hash{$key}, 7;
[download]

See if you have 7 seperate values. If not, then one can say try "\s+" in the split function, instead of the "\t" like so:

 print join "\n",split /\s+/, $hash{$key}, 7;
[download]

If that works, then :-)! You got it!!!

Just a thought:

You may need to replace this:

tie (my %hash, 'DB_File', $file, O_RDWR, 0600) || next;
[download]

with this:

tie (my %hash, 'DB_File', $file, O_RDWR, 0600, $DB_HASH) || next;
[download]

See DB_HASH of DB_File.

Update: The code shown is a fragment which does not compile. Please post a complete example if possible; or, at the least, indicate which line in the fragment shown is the line 66 referenced in the error message.

Plus minor edits.

HTH,