t3_topmail.pl

#!/usr/bin/perl
#
# Program to parse .csv file from mail.log
# and write out top mailers based on number
# and size of mails.
#
# Author: Anton Lindström
# me@antonlindstrom.com
#

use strict;
use warnings;

my $csvfile = "logmail.csv";

# Open and assign $csvfile to @csv
open(CSV, $csvfile);
my @csv = <CSV>;
close(CSV);

# Global variables.
my (%topnum, %topsize, %toprecnum, %toprecsize);

foreach (@csv) {
  # Split csv.
  my ($from, $to, $date, $size, $status) = split(/,/, $_);

  ## Note: Small sizes of mails will cause the kB-function to
  ## make them 0kB in size. Due to heavy mailing in this example
  ## it was nicer to make it this way. It is intended!

  # For every occurance of $from (user email) +1.
  if (exists($topnum{$from})) { $topnum{$from} += 1; }
  else { $topnum{$from} = 1; }
  
  # For every occurance of $from (user email) add $size in kB of message.
  if (exists($topsize{$from})) { $topsize{$from} += int($size/1024); }
  else { $topsize{$from} = int($size/1024); }
  
  # For every occurance of $to (user email) +1.
  if (exists($toprecnum{$to})) { $toprecnum{$to} += 1; }
  else { $toprecnum{$to} = 1; }
  
  # For every occurance of $to (user email) add $size in kB of message.
  if (exists($toprecsize{$to})) { $toprecsize{$to} += int($size/1024); }
  else { $toprecsize{$to} = int($size/1024); }
}

# Call sub print
print "Top 10 mailers (based on number of emails sent):\n";
&print(%topnum);
print "Top 10 mailers (based on size in kB of emails sent):\n";
&print(%topsize);
print "Top 10 recievers (based on number of emails recieved):\n";
&print(%toprecnum);
print "Top 10 recievers (based on size in kB of emails recieved):\n";
&print(%toprecsize);

# Print hashes.
sub print {
  my %hash = @_;
  # Count every foreach to only print 10.
  my $i=0;

  foreach my $key( sort { $hash{$b} <=> $hash{$a} } keys(%hash) ) {
    # Print hash.
    print "\t $hash{$key}\t$key\n";
    # Increment
    $i++;
    # Jump to last if $i=10. 
    last if($i == 10);
  }
}