1. send all failures in one email message
2. instantiate only one Net::Ping and re-use it
3. get rid of the tryagain sub

use strict;
use warnings;
use Data::Dumper;

use Net::Ping;
use MIME::Lite;
use Getopt::Long;
use Pod::Usage;

use vars qw(
   $ping $first $delay $second
   @host $file $help 
   $to $from
);

parse_args();
$to     ||= 'linebacker@perlmonks.org';
$from   ||= 'ICMP Monitor <joeblow@i.com>';
$first  ||= 5;
$delay  ||= 60;
$second ||= 30;

$ping = Net::Ping->new('icmp');

foreach my $host (@host) {
   print "$host is ";
   unless ($ping->ping($host, $first)) {
      sleep ($delay);
      unless ($ping->ping($host, $second)) {
         notify($host);
         print 'NOT ';
      }
   }
   print "reachable.\n";
}

$ping->close();


sub notify {
   my @host = @_;
   my $data = "Ping failures:\n\t" . join("\n\t",@host) . "\n" . local
+time;
   my $msg=MIME::Lite-> new(
      To      => $to,
      From    => $from,
      Subject => 'Ping Failure',
      Data    => $data,
   );
   $msg->send;
}

sub parse_args {
   GetOptions(
      'host=s'   => \@host,
      'file=s'   => \$file,
      'to=s'     => \$to,
      'from=s'   => \$from,
      'first=i'  => \$first,
      'delay=i'  => \$delay,
      'second=i' => \$second,
      'help|h|?' => \$help,
   );

   pod2usage(-verbose=>2) if $help;
   pod2usage(-verbose=>1) unless @host or $file;

   @host = file2list($file) unless @host;
}

sub file2list {
   my $file = shift;
   open FH, $file or die "can't open $file: $!";
   my @list = <FH>;
   chomp @list;
   return @list;
}

__END__

=head1 NAME

ping_mon.pl - Ping Monitor with Email Notification

=head1 SYNOPSIS

ping_mon.pl -host <host> | -file <file>

 Options:
   -file          read list of hosts from file
   -host          provide host via command line
   -to            email recepient
   -from          email sender
   -first         no. seconds for first time-out
   -delay         no. seconds between first and second ping
   -second        no. seconds for second time-out
   -help  -h      brief help message

=head1 DESCRIPTION

B<This program> will ping the provided hosts and send
a email notifying which hosts (if any) were not reachable.  
Each host will first be pinged for an initial amount (set
with the -first option). If that ping fails, the program
will sleep for an amount of time (set with the -delay
option) before a second ping attempt. The second ping's
time-out is set with the -second option. You can also
set the to and from fields for the email on the command
line. Modify the source code to add default values.

=head1 EXAMPLES

1 - ping contents of /etc/hosts

   ./ping_mon.pl -file=/etc/hosts

2 - ping Google

   ./ping_mon.pl -host=google.com

2 - ping Google and Perlmonks

   ./ping_mon.pl -host=google.com -host=perlmonks.org

=cut
[download]

jeffa

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)