Bit stuck here, I've written a bit of code that tails a log file looking for a defined event. This works fine until the log file gets rotated, then, of course, it stops working as the original file I was looking @ has been renamed. Can't think of a elegant way to get around this, any ideas would be helpful. Heres the code I've got so far:

#!/usr/bin/perl

use IO::Handle;
use File::stat;

$sleep = 1; # time to sleep between re-sampling file
$counter = 0;

while ( $_ = shift(@ARGV)) {

        if ( /^-f/ ) { $file = shift (@ARGV); } # log file to monitor
        if ( /^-m/ ) { $max = shift (@ARGV); } # ceiling limit to delt
+a update rates
        if ( /^-r/ ) { $max_exceeds = shift (@ARGV); } # number of tim
+es delta ceiling limit is ignored until being
reported, optional
        if ( /^-l/ ) { $log = shift (@ARGV); } # log file to write to,
+ optional

        if ( /^-c/ ) { $config = shift (@ARGV); } # use config file
}


if ( $config ) {
        open (CFG, "$config") or die "Cannot open config file $config:
+$!\n";
        while (<CFG>) {
                chomp;
                s/#.//;
                s/^\s+//;
                s/\s+$//;
                next unless length;
                my ($var, $value) = split (/\s*=\s*/, $_, 2);
                no strict 'refs';
                $$var = $value;
        }
        close (CFG);
}

unless ( $max ) { $max = 1500; } # default limit for delta

unless ( $limit ) { $limit = 300; } # default to 5 minutes

unless ( $max_exceeds ) { $max_exceeds = 5; } # default limit

if ( $log ) {
        open (STDOUT, "> $log") or die "Cannot write to $log:$!\n";
        STDOUT->autoflush(1);
}

if ( $verbose and $config ) { print "Using configuration file $config\
+n"; }
if ( $verbose ) { print "delta limit set to $max updates per sample pe
+riod (30 seconds)\ndelta exceed timer set to $
limit seconds\nmaximum number of exceeded delta's before reporting is 
+$max_exceeds\n"; }

open (FILE, "$file") or die "Cannot open file $file: $!\n";

for (;;) {
        while (<FILE>) {
                if ( $_ =~ "Delta" ) {

                        @line = split, $_;
                        if ( $verbose ) { print "\nDelta found:\n@line
+\n"; }
                        $delta = $line[4];

                        if ( $delta >= $max ) {

                                if ( $verbose ) { print "Current delta
+ $delta exceeding $max and counter is $counter
\n"; }
                                $now_time = time;

                                # if start time not set or zero, set t
+ime and alarm

                                if ( ! $s_time or $s_time == 0 ) {
                                        $s_time = time;
                                        $alarm = $s_time + $limit;
                                        if ( $verbose ) { print "Alarm
+ set to $alarm, current time $s_time\n"; }
                                        $counter=0;
                                }


                                # if counter is greater than max_excee
+ds and the current time is <= alarm

                                elsif ( $counter >= $max_exceeds and $
+now_time <= $alarm ) {
                                        print "$delta exceeds threshol
+d of $max $counter times\n";
                                        $s_time=0;
                                        $alarm=0;
                                        $counter=0;
                                }

                                # if current time >= alarm reset some 
+variables back to 0, as alarm exceeded

                                elsif ( $now_time >= $alarm ) {
                                        if ( $verbose ) { print "Alarm
+ timer exceeded.....resetting counter, time an
d alarms\n"; }
                                        $counter=0;
                                        $alarm=0;
                                        $s_time=0;
                                }
                                else { $counter++; }

                        }
                }
        }
        sleep $sleep;
        last if stat(*FILE)->nlink == 0;
        FILE->clearerr();
}
close (FILE); 
if ( $log ) { close (STDOUT); }
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