#!/usr/bin/perl
use strict;
use warnings;
my  $timestamp=(`date -u +%Y-%m-%d,%T`);
chomp($timestamp);
print "$timestamp";
open(FI,">forkdata") || die ("Could not open file:$!");
sub ping_a_host {
      my $host = shift;
      @ping_output=`ping $host 16 -n 4 2>/dev/null`;
      if (grep { /round-trip\s+\(ms\)/ ; if ($_ =~ m#min/avg/max\s+=\s
++(\d+)/(\d+)/(\d+)#) {print FI "$host,$timestamp,$1,$2,$3\n"}}  @ping
+_output){
               return 1;}
      elsif (grep {/0 packets rec/} @ping_output){
               print FI "$host,$timestamp,NULL,NULL,NULL\n";
               return 0;
                        }
    }
    my %pid_to_host;
    sub wait_for_a_kid {
      my $pid = wait;
      return 0 if $pid < 0;
      my $host = delete $pid_to_host{$pid}
        or warn("Why did I see $pid ($?)\n"), next;
      warn "reaping $pid for $host\n";
      1;
    }
    my @hosts = map "192.198.192.$_", "221".."251";
    for (@hosts) {
      wait_for_a_kid() if keys %pid_to_host > 10;
      if (my $pid = fork) {
        ## parent does...
        $pid_to_host{$pid} = $_;
        warn "$pid is processing $_\n";
      } else { # child does
        ## child does...
        exit !ping_a_host($_);
      }
    }
    ## final reap:
    1 while wait_for_a_kid();
close FI;
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