Can you please help me in optimizing the code given below.

Sure, but clean up your code first then re-post it. As is, it is almost unreadable.

• Add use strict; and eliminate these warnings:

  Global symbol "$sec" requires explicit package name at - line 100.
  Global symbol "$min" requires explicit package name at - line 100.
  Global symbol "$hour" requires explicit package name at - line 100.
  Global symbol "$mday" requires explicit package name at - line 100.
  Global symbol "$mon" requires explicit package name at - line 100.
  Global symbol "$year" requires explicit package name at - line 100.
  Global symbol "$wday" requires explicit package name at - line 100.
  Global symbol "$yday" requires explicit package name at - line 100.
  Global symbol "$isdst" requires explicit package name at - line 100.
  Global symbol "$year" requires explicit package name at - line 101.
  Global symbol "$mon" requires explicit package name at - line 102.
  Global symbol "$d" requires explicit package name at - line 103.
  Global symbol "$mday" requires explicit package name at - line 103.
  Global symbol "$d" requires explicit package name at - line 104.
  Global symbol "$d" requires explicit package name at - line 105.
  Global symbol "$d" requires explicit package name at - line 105.
  Global symbol "$m" requires explicit package name at - line 107.
  Global symbol "$mon" requires explicit package name at - line 107.
  Global symbol "$m" requires explicit package name at - line 108.
  Global symbol "$m" requires explicit package name at - line 109.
  Global symbol "$m" requires explicit package name at - line 109.
  Global symbol "$year" requires explicit package name at - line 111.
  Global symbol "$m" requires explicit package name at - line 111.
  Global symbol "$d" requires explicit package name at - line 111.
  Global symbol "$sec" requires explicit package name at - line 114.
  Global symbol "$min" requires explicit package name at - line 114.
  Global symbol "$hour" requires explicit package name at - line 114.
  Global symbol "$mday" requires explicit package name at - line 114.
  Global symbol "$mon" requires explicit package name at - line 114.
  Global symbol "$year" requires explicit package name at - line 114.
  Global symbol "$wday" requires explicit package name at - line 114.
  Global symbol "$yday" requires explicit package name at - line 114.
  Global symbol "$isdst" requires explicit package name at - line 114.
  Global symbol "$year" requires explicit package name at - line 115.
  Global symbol "$mon" requires explicit package name at - line 116.
  Global symbol "$d" requires explicit package name at - line 117.
  Global symbol "$mday" requires explicit package name at - line 117.
  Global symbol "$d" requires explicit package name at - line 118.
  Global symbol "$d" requires explicit package name at - line 119.
  Global symbol "$d" requires explicit package name at - line 119.
  Global symbol "$m" requires explicit package name at - line 121.
  Global symbol "$mon" requires explicit package name at - line 121.
  Global symbol "$m" requires explicit package name at - line 122.
  Global symbol "$m" requires explicit package name at - line 123.
  Global symbol "$m" requires explicit package name at - line 123.
  Global symbol "$year" requires explicit package name at - line 125.
  Global symbol "$m" requires explicit package name at - line 125.
  Global symbol "$d" requires explicit package name at - line 125.
  Global symbol "$outfile" requires explicit package name at - line 127.
  Global symbol "$outfile" requires explicit package name at - line 129.
  Global symbol "$outfile" requires explicit package name at - line 129.
  Global symbol "$filename" requires explicit package name at - line 131
  +.
  Global symbol "$index" requires explicit package name at - line 133.
  Global symbol "$filename" requires explicit package name at - line 133
  +.
  Global symbol "$index" requires explicit package name at - line 134.
  Global symbol "$filename" requires explicit package name at - line 137
  +.
  Global symbol "$filename" requires explicit package name at - line 138
  +.
  Global symbol "$sourcefile" requires explicit package name at - line 1
  +38.
  Global symbol "$filename" requires explicit package name at - line 144
  +.
  Global symbol "$ct" requires explicit package name at - line 151.
  Global symbol "$ct" requires explicit package name at - line 152.
  Global symbol "$ct" requires explicit package name at - line 153.
  Global symbol "$ct" requires explicit package name at - line 154.
  Global symbol "$ct" requires explicit package name at - line 156.
  Global symbol "$sourcefile" requires explicit package name at - line 1
  +58.
  Global symbol "$ct" requires explicit package name at - line 170.
  Global symbol "$ct" requires explicit package name at - line 171.
  Global symbol "$ct" requires explicit package name at - line 171.
  Execution of - aborted due to compilation errors.
  [download]

  That will save everybody here from having to track down that the reason for this:

  Global symbol "$sourcefile" requires explicit package name at - line 1
  +58.
  [download]

  Is because of lines like this:

  open(OLD,"/inside29/urchin/test/logfiles/$filename") || die ("Cud not 
  +open the $sourcefile");
  [download]

  and this

  open(OLD,"consolidatedlog.txt") || die ("C not open the $sourcefile");
  [download]

  It is quite handy if your error messages refer to the same files as those that cause the errors!

  And sorry for mentioning this, but what is all this?

  my $yesterday = time() - ( 24 * 60 * 60 ); ## Why use 'my' here ######
  +###########
  
  ## And not here -v-v-v-v-v-v-v-v- #####################
  ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localtime($yes
  +terday);
  $year += 1900;
  $mon++;
  $d = "$mday"; ## <<< Why copy $mday to $d? And why quote "$mday"?  ###
  +######################
  if ($d <10) {
          $d = "0$d"; ## <<< What does this do? #################
  }
  $m ="$mon";
  if ($m<10) {
          $m = "0$m"; ## <<< And this? ####################
  }
  $yesterday = "$year" . "$m" . "$d"; ## Why all those "s? #######
  [download]

  Please don't take this to heart, but asking us to optimise your code, when it is so ... um ... messy, is rather pushing your luck a little.

  ---

  Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

  Lingua non convalesco, consenesco et abolesco.

  Rule 1 has a caveat! -- Who broke the cabal?

  Comment on Re: Reduce the time taken for Huge Log files Select or Download Code