# Create a list of all possible IP addresses within subnet
open(ALLIP, ">allip.list") || die "Unable to create file: allip.list\n";
for ($i=0; $i<=20; $i++) {
        print ALLIP "$ip_subnet.$i\n";
}
open(ALLIP, "allip.list") || die "Unable to open file: allip.list\n";
open(PINGALLIP, ">pingallip.list") || die "Unable to open file: pingallip.list";
while (<ALLIP>) {
        system("ping $_ >pingallip.list") && "Unable to create file: pingallip.l
ist";
chomp; }
open(OUTPUT, ">output.list");
open(PINGALLIP, "pingallip.list") || die "Unable to open file: pingallip.list";
my $line = 0;
while (<PINGALLIP>) {
chomp;
#my $line = 0;
#while (<ALLIP>) {
#chomp;
        if ($_ eq~ m/is alive/) {
                $line++;
                last;
        }
}
      close(ALLIP);

        if ($line) {
                print OUTPUT "$_\n";
        } else {
                print "ERROR\n";
        }