my @result = `ping -c 4 hostname`;

if ping -c 4 example.com
then
  echo 'Alles klar'
  exit 0
else
  echo 'Ping geht nicht, ich versende eine eMail'
  sendmail -t <<EOF
From: me@here
To: you@there
Subject: Host down
EOF
   [ $? != 0 ] && echo 'Sendmail geht auch nicht :-('
   exit 1
fi

$mail="recipient\@domain.net";
$linux="sender\@domain.net"; 
$host="X.X.X.X";
$out=`ping -c8 $host | grep -c "bytes from"`;
if($out < 7){
open(MAIL, "|/usr/sbin/sendmail -t");
print MAIL "to:$mail\n";
print MAIL "from:$linux\n";
print MAIL "subject:server down !\n";
print MAIL "hi \n\n";
print MAIL "cannot ping server X.X.X.X \n\n";
print MAIL "Time: ". localtime(time) ." \n";
close(MAIL);
}
exit;

#! /usr/bin/perl
use warnings;
use strict;
use Net::Ping;

my $host = 'irgendeinServer';
my $pingCount = 4;
my $ping = Net::Ping->new('icmp') 
  or die "Error in creating Net::Ping-Object: $!\n";

if (my $count = grep { $ping->ping($host) } 1..$pingCount) {
  print "$count von $pingCount Versuchen erfolgreich";
} # if
else {
  # mail versenden hier, z.B. mit Mail::Sendmail, MIME::Lite, ...
  # ...
}

sub Ping
{ my $ip = shift;   # Übergabe IP-Adresse
  my $pingmax = PingMax;
  my $answer = `ping -w 1000 -n $pingmax $ip`;
  DosToWin \$answer;   # Umlaute umwandeln
  my $number = scalar $answer =~ s/(Bytes=32)/$1/mg;
  $number == PingMax or do
  { $answer =~ s/^\s*\n//;   # führende Leerzeilen löschen
    $answer =~ s/\n\s*\n/\n/g;   # Leerzeilen löschen
  };
  return $number;
}