use strict;
use warnings;
use Socket;

my @ip = ( '159.230.1.1 255.255.224.0',
           '159.230.1.20 255.255.252.0',
           '158.230.1.3 255.255.255.0',
           '159.230.1.3 255.255.255.0',
           '159.230.1.20 255.255.1.1' );

print join ("\n", @ip);
print "\n\n";

my %count;
foreach (@ip) {
  $count{inet_aton($&)}++ if /159\.230\..*?( |$)/;
}

open(FILE, '>ip.txt');

foreach (sort keys %count) {
  print inet_ntoa($_)." appears $count{$_} times.\n";
  print FILE inet_ntoa($_)."\n";
}

close FILE