Optimize shell code

Shell Programming and Scripting
1 
#!/usr/bin/perl
use strict;
use warnings;

use Date::Manip;
my $date_converted = UnixDate(ParseDate("3 days ago"),"%e/%h/%Y");
open FILE,">$ARGV[0]";

while(<DATA>){

my @tab_delimited_array = split(/\t/,$_);
  $tab_delimited_array[3] =~ s/^\[//;
  $tab_delimited_array[3] =~ s/^\-//;
        my $converted_date = Date_ConvTZ( UnixDate($tab_delimited_array[3],"%Y%m%d%H:%M:%S"),'GMT','PST');
        my $pst_converted_date = UnixDate($converted_date,"%e/%h/%Y:%H:%M:%S");
        $pst_converted_date =~ s/^\s//g;
        my $extracted_YMD=UnixDate($converted_date,"%e/%h/%Y");
if($extracted_YMD =~ m/$date_converted/){
print FILE $_;
}
}

close FILE;
close DATA;


__DATA__
66.249.65.43    www.cabc.com    -       3/Jul/2010:19:00:01     +0000   "GET http://www.abc.com HTTP/1.1"       200     0.730   7362    0       0       -       -       Mozilla/5.0+(compatible;+Googl/2.1;+\+http://www.google.com/bot.html)   TCP_MISS
66.249.65.43    www.cabc.com    -       4/Jul/2010:19:00:01     +0000   "GET http://www.abc.com HTTP/1.1"       200     0.730   7362    0       0       -       -       Mozilla/5.0+(compatible;+Googl/2.1;+\+http://www.google.com/bot.html)   TCP_MISS
66.249.65.43    www.cabc.com    -       2/Jul/2010:09:00:01     +0000   "GET http://www.abc.com HTTP/1.1"       200     0.730   7362    0       0       -       -       Mozilla/5.0+(compatible;+Googl/2.1;+\+http://www.google.com/bot.html)   TCP_MISS
66.249.65.43    www.cabc.com    -       3/Jul/2010:09:00:01     +0000   "GET http://www.abc.com HTTP/1.1"       200     0.730   7362    0       0       -       -       Mozilla/5.0+(compatible;+Googl/2.1;+\+http://www.google.com/bot.html)   TCP_MISS

---------- Post updated at 02:26 AM ---------- Previous update was at 02:25 AM ----------

The file is very large and it takes long time to execute.
The input is tab delimited file

2

I guess you need find out the old logs which convert the date from GMT to PST first, and 3 days ago.

Use GNU date, you can get it in one line command.

date -d "-3 days -8 hours" +%e/%h/%Y |xargs -i grep {} urfile
3

Our machine will not support GNU date :frowning:

---------- Post updated 07-07-10 at 05:02 AM ---------- Previous update was 07-06-10 at 10:30 AM ----------

Other than GNU date, how can I optimise the code