Well, looking at the code you've provided showing what you've tried so far . . .

Oh, you didn't. Never mind.

Read the line. Extract the timestamp. Parse the timestamp (see Date::Manip, Date::Calc). Compare with now. Print if it's within your window.

Update:

require 'time'

now=Time.now

ARGF.each do |line|
  next unless line =~ /(.*?) : Depth/
  d_days = ( now - Time.parse( $1 ) ) / 86400
  puts line if d_days < 45
end
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The code worked for me. The only trick, it would appear, is to first run ln -s /usr/bin/ruby /usr/bin/perl.
I was initially inclined to downvote the node for the horrible blasphemy of posting non-Perl code in the Monastary. Then I saw in my mind's eye the OP pasting the code into a file and trying to run it... what the... missing semicolon? I thought these guys knew their stuff!.
So ++Fletch. I have Programming Ruby sitting on my bedside table, but have only browsed it so far. Ruby appears to be popular in Asia, and I really enjoyed some dabbling I've done in Smalltalk, so it might be right up my alley.

Blasphemy for not using perl? Remember: TMTOWTDI, and some of the W's don't even involve perl . . . :)

But yes that's kind of the point of using Ruby, especially if it's got a whiff of that homework smell about it (as this did) or if they've not shown any attempt at making an effort (again, as this did). Much of Ruby's close enough to Perl conceptually that you can (almost) see the equivalent Perl if you squint hard enough. Not to mention it gives an excellent chance for me to practice my Ruby.

graff/fletch/tedpride/, Thank you very much The CODE WORKS!!!! Regards Greatfull

Hi Fletch/TedPride, Thank you for the update ..BUT I am not sure if this gets all the records for the last 45 days. I did try the code you pasted...but its not showing all the records for the last 45 days Is there any other way of doing this in either perl or unix.

As for your problem, if you look at the docs for the first module suggested in the first reply, and just play with Date::Manip in the simplest possible experiment, I think you'd get what you want. For example (replacing your bad sample data with some relevant data):

#!/usr/bin/perl

use strict;
use Date::Manip;

my $limit = DateCalc( 'now', '- 45 days' );

while (<DATA>) {
    my $datestr = (split / : /)[0];  # note spaces around ":"
    print if ( ParseDate( $datestr ) > $limit );
}

__DATA__
Fri Dec  3 23:07:21 EST 2004 : Depth is : 234
Sat Dec  4 00:07:29 EST 2004 : Depth is : 123
Sat Feb 26 14:13:12 EST 2005 : Depth is : 4567
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use strict;
use warnings;

my $time = time(); my $days = 45;
my ($day, $mon, $mday, $hour, $min, $sec, $zone, $year, $depth, $flag)
+;

while (read(DATA, $_, 45)) {
    if (!$flag) {
        ($day, $mon, $mday, $hour, $min, $sec, $zone, $year, $depth) =
            unpack('A3xA3xA2xA2xA2xA2xA3xA4x14A3', $_);
        # Use module to convert to timestamp $mytime
        if ($mytime > $time - 86400 * $days) {
            print $depth; $flag = 1;
        }
    }
    else {
        ($depth) = unpack('x42A3', $_);
        print $depth;
    }
}

__DATA__
Fri Dec  3 23:07:21 EST 2004 : Depth is : 234Sat Dec  4 00:07:29 EST 2
+004 : Depth is : 123Sat Dec  5 03:07:32 EST 2004 : Depth is : 144
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Problem is, I don't know a good module for creating a timestamp out of the date information. Maybe someone else can insert that part for me?

I would recommend you dump the data into a database, then get the database to extract the data you want.