2005-01-05 Janitored by Arunbear - added readmore tags, as per Monastery guidelines

You have an interesting case here. Personally, I don't see anything wrong with the approach you've started with, and I think trying to stuff subroutine refs into the GetOpt::Long usage to handle option dependencies is just going to obfuscate things. You don't need to go there, IMO. (I would especially advise against any approach the requires the options to be given in a specific order; this goes against the nature of option usage as most command-line users understand it.)

Apart from that, I have just a few nit-picks:

• Running the script with no args looks like a no-op; this should be treated the same as using the "-h|--help" option.
• You might consider working on the pod a bit... see if you can indicate some of the option dependencies in the synopsis, and/or re-order the list of options so the dependencies are more salient and make sense on first glance.
• For heaven's sake, provide an appropriate DESCRIPTION that at least gives an idea about what happens when the various settings are activated.
• Your "make_dirs" sub could be using the Perl-internal "mkdir" and "chmod" functions, rather than running a bunch of system calls, and I'm not sure what you gain by using  !system "ls ..." or die as opposed to, say,  ( -d "..." ) or die
• You have a "get_line" sub that is never called; I think it's very good that you never actually use this sub, and it would be fine to remove it from the script.

I guess the path I'm taking will work. I just assumed that someone had been down this path before and had come up with a comprehensive way of handling options in a multi-purpose script. I definitely agree that the script should not require that options be given in a specific order. Thanks for the nit-picks! I plan to add a --help option or use auto_help built in to the module. The POD needs work, that's for certain. Hah! The description was nabbed straight from the Getopt::Long docs. I'll change it. Um, I forgot about mkdir and chmod builtins. The ls function is necessary, but the die is not. Since I'm using automount, the filesystem isn't mounted until the path is read. I suppose I could mount the filesystem to a temp location, but that seems like more work, more lines of code, more cleanup. The get_line sub and the remove_line subs are not currently being used. I should have removed them before posting.

I was hoping to be able to require the dependent options within the getopt module

This is how I handle option dependecies. Whether it's clearer than your method is largely a matter of taste. You keep a dependecy near the code that mandates it. I group all of them near the GetOptions call.

use Getopt::Long;
use Pod::Usage;

my %opt;

GetOptions(
           \%opt,
           'help',
           'man',
           'V|version',
           't|timeout=i',
           'H|hostname=s',
           'p|port=i',
           'U|uri=s',
          ) or pod2usage(2);

# standard opt handling;
$opt{h}   && pod2usage(1);
$opt{man} && pod2usage( -exitstatus => 0, -verbose => 2 );
$opt{V}   && version();

# option dependencies
( defined($opt{U}) xor defined($opt{H}) ) || pod2usage(1);
defined($opt{H}) && defined($opt{p})      || pod2usage(1);


# ... go on your merry way knowing dependencies are satisfied

__END__

=head1 NAME

    opttest - Check out Getopt::Long and Pod::Usage

=head1 SYNOPSIS

    opttest [options] -U uri
      - or -
    opttest [options] -H <hostname> -p <port>

     Options:
       U | -uri         uri to check
       
       H | -hostname    hostname to check
       p | -port        tcp port to check (required with hostname!)
       ...

=head1 DESCRIPTION

    Optest provides some basic option handling and demonstrates
    how to handle option dependencies for most-likely cases.

=cut
[download]

Adding some feedback to the user also helps the code self-document, but does create some clutter:

( defined($opt{U}) xor defined($opt{H}) )
  || do { print "Only one of 'hostname' or 'uri' must be specified\n";
          pod2usage(1);
        };
defined($opt{H}) && defined($opt{p})
  || do { print "Hostname option requires port option\n";
          pod2usage(1);
        };
[download]

--Solo

--
You said you wanted to be around when I made a mistake; well, this could be it, sweetheart.

Thank you. This will help me. I learn best by example for some reason. I would rather use a method for grouping the dependencies near the top. My method comes from a shallow bag of tricks.