#! /usr/bin/perl -wT

# Perl script to check disk usage and send emails to users hogging
# more than a specified limit. Needs to be run as root and a good way to do
# it is via a cron job.
# 
# First written : Patrick Krogel, Fri Feb 24 11:51:35 EST 2006 (perl version)
# Last modified : Patrick Krogel, Fri Feb 24 11:56:40 EST 2006
#                 Gowtham Fri Feb 24 15:37:40 EST 2006
# 

# Variable initializations
$date    = localtime;
$dulimit = 20;   # Disk Usage Limit, in GB

# Get the disk usage, in GB, and separate out space and uids 
open PIPE, "du -s -B 1024M /home/* |" or die "Can't get disk usage.\n";
while (<PIPE>)
{
   chomp;
   my ($space, $user) = split /\s+/;
   $user =~ s/^.*\/(\w+)$/\1/;
   if ($space > $dulimit)
   {
      # Debugging purposes only! 
      # print "$user is taking up $space GB\n";
      open MAIL, "| mail -s 'Disk Usage Notification' $user\@domain.name"
        or die "Can't send email.\n";
      print MAIL "$user,\n\n";
      print MAIL "Your home folder,\n\n";
      print MAIL "/home/$user ($space GB)\n\n";
      print MAIL "in 'host.domain.name' has exceeded the present limit.\n";
      print MAIL "Please back it up elsewhere (some other machine or\n";
      print MAIL "external hard drives) and clean up the home folder.\n\n";
      print MAIL "root\@host.domain.name\n";
      print MAIL "$date\n";
      close MAIL;
   }
}
close PIPE;