Getopt::Simple (3pm)

        use Getopt::Simple;

        # Or ...
        # use Getopt::Simple qw($switch);

        my($options) =
        {
        help =>
                {
                type    => '',
                env     => '-',
                default => '',
#               verbose => '',      # Not needed on every key.
                order   => 1,
                },
        username =>
                {
                type    => '=s',    # As per Getopt::Long.
                env     => '$USER', # Help text.
                default => $ENV{'USER'} || 'RonSavage', # In case $USER is undef.
                verbose => 'Specify the username on the remote machine',
                order   => 3,       # Help text sort order.
                },
        password =>
                {
                type    => '=s',
                env     => '-',
                default => 'password',
                verbose => 'Specify the password on the remote machine',
                order   => 4,
                },
        };

        my($option) = Getopt::Simple -> new();

        if (! $option -> getOptions($options, "Usage: testSimple.pl [options]") )
        {
                exit(-1);       # Failure.
        }

        print "username: $$option{'switch'}{'username'}. \n";
        print "password: $$option{'switch'}{'password'}. \n";

        # Or, after 'use Getopt::Simple qw($switch);' ...
        # print "username: $$switch{'username'}. \n";
        # print "password: $$switch{'password'}. \n";

\*(C`Getopt::Simple\*(C' is a pure Perl module.

The \*(C`Getopt::Simple\*(C' module provides a simple way of specifying:

• Command line switches

• Type information for switch values

• Default values for the switches

• Help text per switch

This module is available both as a Unix-style distro (*.tgz) and an ActiveState-style distro (*.ppd). The latter is shipped in a *.zip file.

See http://savage.net.au/Perl-modules.html for details.

See http://savage.net.au/Perl-modules/html/installing-a-module.html for help on unpacking and installing each type of distro.

new(...) returns a \*(C`Getopt::Simple\*(C' object.

This is the class's contructor.

Usage: Getopt::Simple -> new().

This method does not take any parameters. \*(C`dumpOptions()\*(C' prints all your option's keys and their current values.

\*(C`dumpOptions()\*(C' does not return anything. The \*(C`getOptions()\*(C' function takes 4 parameters:

• A hash ref defining the command line switches The structure of this hash ref is defined in the next section. This parameter is mandatory.

• A string to display as a help text heading This parameter is mandatory.

• A Boolean. 0 = (Default) Use case-sensitive switch names. 1 = Ignore case This parameter is optional.

• A Boolean. 0 = Return after displaying help. 1 = (Default) Terminate with exit\|(0) after displaying help This parameter is optional.

\*(C`getOptions()\*(C' returns 0 for failure and 1 for success.

• Each key in the hash ref is the name of a command line switch

• Each key points to a hash ref which defines the nature of that command line switch The keys and values of this nested hash ref are as follows.

  • default => 'Some value' This key, value pair is mandatory. This is the default value for this switch. Examples: default => '/users/home/dir' default => $ENV{'REMOTEHOST'} || '127.0.0.1'

  • env => '-' || 'Some short help text' This key, value pair is mandatory. This is help test, to indicate that the calling program can use an environment variable to set the default value of this switch. Use '-' to indicate that no environment variable is used. Examples: env => '-' env => '$REMOTEHOST' Note the use of ' to indicate we want the $ to appear in the output.

  • type => 'Types as per Getopt::Long' This key, value pair is mandatory. This is the type of the command line switch, as defined by Getopt::Long. Examples: type => '=s' type => '=s@',

  • verbose => 'Some long help text' This key, value pair is optional. This is long, explanatory help text which is displayed below the help containing the three columns of text: switch name, env value, default value. Examples: verbose => 'Specify the username on the remote machine', verbose => 'Specify the home directory on the remote machine'

  • order => \d+ This key, value pair is mandatory. This is the sort order used to force the help text to display the switches in a specific order down the page. Examples: order => 1 order => 9

  \*(C`helpOptions()\*(C' prints nicely formatted help text.

\*(C`helpOptions()\*(C' does not return anything.

Command line option values are accessed in your code by dereferencing the hash reference $$classRef{'switch'}. Two examples are given above, under synopsis.

Alternately, you can use the hash reference $switch. See below. Command line option values are accessed in your code by dereferencing the hash reference $switch. Two examples are given above, under synopsis.

Alternately, you can use the hash reference $$classRef{'switch'}. See above.

As always, be aware that these 2 lines mean the same thing, sometimes:

• $self -> {'thing'}

• $self->{'thing'}

The problem is the spaces around the ->. Inside double quotes, \*(L"...\*(R", the first space stops the dereference taking place. Outside double quotes the scanner correctly associates the $self token with the {'thing'} token.

I regard this as a bug.

\*(C`Getopt::Simple\*(C' was written by Ron Savage <[email protected]> in 1997.

Australian copyright (c) 1997-2002 Ron Savage.

All Programs of mine are 'OSI Certified Open Source Software'; you can redistribute them and/or modify them under the terms of The Artistic License, a copy of which is available at: http://www.opensource.org/licenses/index.html