Any ideas please

1. Write tests - lots of them. Dates are tricky, illogical things (months have varying numbers of days, timezones affect what the current date is, remember about leap years, etc.).
2. Construct an algorithm to produce the desired output.
3. Code up the algorithm.
4. Run the tests and adjust the code and/or algorithm until they all pass.

Which specific part of all this are you having trouble with?

Maybe use Time::Piece to generate the added days.

#!perl
use strict;
use Time::Piece;
use Time::Seconds 'ONE_DAY';

my $process_date  = '20161002';
my $t = Time::Piece->strptime($process_date,"%Y%m%d");
#my $t = Time::Piece->new(); # today
print "Process date is ".$t->ymd('')."\n";

my $data_date  = '20160930';
my $d = Time::Piece->strptime($data_date,"%Y%m%d");
print "Date in data is ".$d->ymd('')."\n";

$d += ONE_DAY;
while ($d <= $t){
  print "   Add date ".$d->ymd('')."\n";
  $d += ONE_DAY;
}
[download]

What code have you already written and where are you encountering problems?

I assume that your input data will either be space delimited or fixed width, so split or unpack might be of help. For bringing the data in date order, sort will likely help. For filtering the data for the report run date, see grep.

Usually, it helps us help you much better if you post an SSCCE as a starting point for the discussion. That shows us where you are and allows us to give you much better directions on how to get to where you want to be.

#!/usr/bin/perl

# http://perlmonks.org/?node_id=1178418

use strict;
use warnings;

sub eightdigitdate
  {
  my @fields = localtime(shift);
  sprintf '%04d%02d%02d', $fields[5] + 1900, $fields[4] + 1, $fields[3
+];
  }

sub nextday
  {
  use Time::Local;
  shift() =~ /(\d{4})(\d\d)(\d\d)/;
  eightdigitdate( 60*60*24 + timelocal 0, 0, 12, $3, $2 - 1, $1 );
  }

#my $today = eightdigitdate(time);
my $today = '20161002';

print scalar <DATA>;
print my @data = <DATA>;

my $more = 1;
while($more)
  {
  for(@data)
    {
    my $date = (split)[1];
    if( $date < $today )
      {
      s/\b$date\b/ nextday($date) /e;
      print;
      }
    else
      {
      $more = 0;
      }
    }
  }

__DATA__
F12    F11            F481               F55     F989
8204    20160930    1064.848    test    Y
8204A    20160930    1064.505    test    Y
8204B    20160930    1045.469    test    Y
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Tried something like this But couldnt get the required ,Any help APPRECIATED

 
#!/usr/bin/perl

my $isHeader = 1;
my $targetDate = 20161002;

foreach (<STDIN>){
    if (!$isHeader){
    my ($M12,$M11,$M481,$M55,$M989) = split(' ',$_);
    if ($M11 <= $targetDate){
        print $_;
    }
    }
    $isHeader = 0;
}
[download]

Are your input data columns really separated by a space? In the sample above it looks like it may be tabs, in which case your regexp won't match. Maybe try:

split(/\s+/, $_);
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Hope this helps!



The way forward always starts with a minimal test.

#!/usr/bin/perl

# http://perlmonks.org/?node_id=1178418

use strict;
use warnings;

sub eightdigitdate
  {
  my @fields = localtime(shift);
  sprintf '%04d%02d%02d', $fields[5] + 1900, $fields[4] + 1, $fields[3
+];
  }

sub nextday
  {
  use Time::Local;
  shift() =~ /(\d{4})(\d\d)(\d\d)/;
  eightdigitdate( 60*60*24 + timelocal 0, 0, 12, $3, $2 - 1, $1 );
  }

#my $today = eightdigitdate(time);
my $today = '20161002';

print scalar <STDIN>;
print my @data = <STDIN>;

my $more = 1;
while($more)
  {
  for(@data)
    {
    my $date = (split)[1];
    if( $date < $today )
      {
      s/\b$date\b/ nextday($date) /e;
      print;
      }
    else
      {
      $more = 0;
      }
    }
  }
[download]

See Markup in the Monastery for description of other tags.

Update: I see that you updated the code tags. Thanks!
Another Perl module to consider is Date::Time.