use strict;
use warnings;
use Pod::Usage;
use Getopt::Long;

our($file,$range,$help);

GetOptions(
   'file|f=s' => \$file,
   'ip|i=s'   => \$range,
   'help|h'   => \$help,
);

pod2usage(-verbose=>2) if $help;

unless ($file or $range) {
   $file = shift or pod2usage(-verbose=>1);
}
if ($file) {
   open FH, '<', $file or die "can't read $file\n";
   chomp($range = <FH>);
}

print "$range\n";

__END__
=head1 NAME

foo.pl - does something with IP range

=head1 SYNOPSIS

foo.pl [filename] [-file filename] [-ip IPrange]

 Options:
   -file    -f        file to read
   -ip      -i        IP range
   -help    -h        help message

=head1 EXAMPLES

Read from file:
   foo.pl ip.txt
   foo.pl -f ip.txt
   foo.pl -file ip.txt

Read from STDIN:
   foo.pl -i 127.0.0.1
   foo.pl -ip 127.0.0.1