RE:  Need PERL script to parse a log file from the last 24 hours

Posted on 2010-11-29
Last Modified: 2013-11-13
   I'd like someone to assist me with creating a PERL script that will parse a log file based on time (initially I will start with the last 24 hours).  The file will look like this:

[2010-11-29 12:05:29,391 -0800]    "6 digit number" "text"

I hope this is enough information.
Question by:unix_admin_1234
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LVL 10

Accepted Solution

jeromee earned 250 total points
ID: 34235067
Try this:
perl -MPOSIX -ne'BEGIN{$since=strftime("%Y-%m-%d %H:%M:%S", localtime(time-(3600*24)))} print if substr($_,1) ge $since' your_file_here

Author Comment

ID: 34237395
Is there any way to put this in a script as opposed to a one-liner?  I need to incorporate this into a larger script?  Also, a quick summary of this small script would be great.

Thanks!  It look promising though I haven' tried it yet.

Assisted Solution

chrios earned 250 total points
ID: 34238859
This is basically a script version of jeromee's oneliner. Since I changed the output from strftime we dont need to cut (substr) anything before comparing the time to the lines from the log, so this should be a bit easier to understand.

ge = greater or even, string compare

#!/usr/bin/perl -w
use POSIX qw(strftime);

$file = "myfile.txt";
$datestr=strftime("[%Y-%m-%d %H:%M:%S]", localtime(time-3600*24));

open(FH, "<$file") or die "Could not open $file: $!\n";

    print if $_ ge $datestr;


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LVL 10

Expert Comment

ID: 34240531
chrios's "translation" looks good.
I would have added a "use strict" and "my" since it's a good practice.

#!/usr/bin/perl -w

use strict;
use POSIX qw(strftime);

my $file = "myfile.txt";
my $datestr = strftime("[%Y-%m-%d %H:%M:%S]", localtime(time-3600*24));

open(FH, "<$file") or die "Could not open $file: $!\n";

while(<FH>) {
    print if $_ ge $datestr;


Open in new window


Author Comment

ID: 34477785
Thanks everyone..Both scripts seem to work sorry for the late reply.

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