#!/usr/bin/perl -w
#       /usr/local/bin/webalert.pl [mail address] [web address]
use strict;
use LWP;
local *MAIL;

# get the mail address if there is one.
my $mailaddr = shift @ARGV;

# get the web address if there is one.
my $webaddr = (shift @ARGV ||"www.perlmonks.org");

my $timeout = 15;
if (system "/usr/bin/lwp-request -t $timeout $webaddr >/dev/null 2>&1") {
  sendmail_or_print()
  }

sub sendmail_or_print {

  # get the mail address if there is one.
  my $hostname = "from ". (`hostname 2>/dev/null` ||"who");

  # get the mail address if there is one.
  if ($mailaddr) {
    open MAIL, "|mail -s \"Web Alert $hostname\" $mailaddr";
    }
  else {
    open MAIL, ">&STDOUT";
    }

  print MAIL "\n\n$webaddr NOT available: " . localtime() ."\n\n";
  print MAIL "$timeout second timeout used.\n\n";
  close MAIL;
  }