#this source was developed by Rob Meerwijk, Netherlands
#you can freely distribute it
#I have tested this script on my readynas NV+
#It is intended for a graceful shutdown of Linux systems connected to a APC BACKUPS HS-500VA
#There is no warranty from me for any data loss as a direct or indirect result of using this script

#call it similar like this from cron every minute: 
#"/usr/bin/perl /<home-dir>/bin/ups-gracefull-shutdown >><home-dir>/log/ups_log" using the correct paths
#check the path of your init script, mine is /sbin/init
#good luck!!!

use LWP::Simple;

# load status from webpage
$status = get('http://ups-1/status.cgi');

#get Local time
my $Timestamp=localtime();

# get battery status for remaining power
$status =~ /align=absmiddle>&nbsp;(\d{1,}).&nbsp;%/;
$battery_status=$1;

if ( $status =~ /Available/ ) { 
   if ( $status =~ /On&nbsp;Line/ ) {
      # Power normal
      if ($Timestamp =~ /:00:/ or $battery_status < 100) {
         # only on the hour write the status to the log
         print "ups-gracefull-shutdown: $Timestamp Normal operation: $battery_status %\n";
      }
      exit 0;
   } 

   else {
      if ( $status =~ /On&nbsp;Battery/ ) {
         print "ups-gracefull-shutdown: $Timestamp Battery operation: $battery_status %\n";

         if ($battery_status < 40) {
            # shutdown, or die, battery power too low
            print "ups-gracefull-shutdown: $TimeStamp Shutting down, low battery\n";

            #send a mail
            system("/bin/echo ups-1 down | mail -s \"Power loss\" yourname\@yourdomain.somecountry");

            #wait a bit before going down
            system("bin/sleep 6");
            system("/sbin/init 0");
            exit -1;
         }
      }
   }
}
else {
     #webpage probably unavailable
     print "ups-gracefull-shutdown: $Timestamp Status page unavailable\n";
     exit -2;
}