#!/usr/bin/perl
use warnings;
use strict;
use Socket qw( inet_aton inet_ntoa);

# takes file paths as argument
for (@ARGV) {
    local $, = $/;
    open my $fh, '<', $_ or die $!;
    print map  { inet_ntoa($_) }
          sort { $a <=> $b }
          map  { chomp; inet_aton($_) }
          <$fh>;
    print $/;
    close $fh or die $!;
}