Tailing logs

[Steve Bertrand]

DAve wrote:
> I would love to have a way to tail a log, like piping to grep, except I 
> see every line and the lines I would normally grep for are highlighted. 
> That would be cool. Anyone know of a bash command or tool that will do 
> this?
> 
> Side note, I am tailing sendmail after changes to my outbound queue 
> runners. I want to highlight my sm-mta-out lines but still see all lines.

A little late to the party now, but the following Perl script will 
'highlight' the lines containing $pattern with a blank line above and 
below, surrounded by ****. The lines not matching will be printed 
normally. Note, File::Tail must be installed:

#!/usr/bin/perl
# grep.pl

use warnings;
use strict;
use File::Tail;

my $pattern = "submission";
my $log = "/var/log/maillog";
my $ref=tie *FH,"File::Tail",(name=>$log, maxinterval=>3);

while (<FH>) {

         if ($_ =~ /$pattern/) {
                 chop ($_);
                 print "\n**** $_ ****\n\n";
         } else {
                 print "$_";
         }
}


pearl# ./grep.pl

**** Aug 22 11:30:45 pearl vpopmail[65893]: vchkpw-submission: 
(CRAM-MD5) login 
                  success steve at ibctech.ca:2607_f118__5 ****

Aug 22 11:31:19 pearl spamd[32860]: spamd: connection from localhost 
[127.0.0.1] 
             at port 57092
Aug 22 11:31:19 pearl spamd[32860]: spamd: processing message 
<6e3e383b080822071 
                   4g37a6ee4bu21e99ebc9e123ab7 at mail.gmail.com> for 
iaccounts at ibctech.ca:58


**** Aug 22 11:31:46 pearl vpopmail[66048]: vchkpw-submission: 
(CRAM-MD5) login success steve at ibctech.ca:2607_f118__5 ****

Aug 22 11:31:56 pearl spamd[95770]: prefork: child states: II