Perhaps something like the following might help you: 
my $filename = "anything.ldif";

unless (open (LDIF, $filename)) {
  die "Error: couldn't read from '$filename': $!\n";
}
else {
  my %seenObjects = ();

  local $/ = "\n\n"; # read objects, not lines

  while (<LDIF>) { # $_ has one object now
    chomp($_);
    s/\n //g; # kill continuation lines

    if ($seenObjects{$_}++) {
      # object already seen... write to another filehandle
      print OUTFILE "$_\n\n";

    } # if

  } # while
  close (LDIF);
} # else

[download]
(Code not tested)

If the LDIF file is very big, you could either save the Digest::MD5 of the object: 

use Digest::MD5 (); # no namespace pollution
...
if ($seenObjects{ &Digest::MD5::md5_hex($_) }++) {
...

[download]
or sort the LDIF (e.g. with Tie::File) and compare one line with its precessor.

Best regards,
perl -e "s>>*F>e=>y)\*martinF)stronat)=>print,print v8.8.8.32.11.32"

In reply to Re: Help needed on text file/String manipulation by strat
in thread Help needed on text file/String manipulation by chinkusimon

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.