#!/usr/bin/perl -w

use strict;
my @octets8;
my $ip = shift;

unless (defined $ip) {
    print 'Enter *something* for input';
    usage();
}   

for (split /\./, $ip) {
    my $err = "$ip don't cut it:  $_";

    if    ( !/^\d{1,3}$/ ) {
        print "$err ain't a number.";
        usage();
    }
    elsif ( $_ > 255 ) {   
        print "$err is greater than 255.";
        usage();
    }
    else {
        my $oct = sprintf "%lo", $_;
        push @octets8, ($oct > 7) ? "0$oct" : $oct;
    }
}
      
print "\n decimal ", $ip,
      "\n octal   ", join('.',@octets8),
      "\n\n";


sub usage {
    print join "\n  ",
          "\n  Usage:  ipdec2oct.pl dottedquad_decimal_ipaddr\n",
          $0, "Perl $]", $^O, "\n";
    exit;
}