Using Getopt::Long you can do this by having a section where you declare all of your variables, a second one where you initialize them with default values, then call GetOptions, then have your main script.

So you can do something like this.

my ($action, $type, $foo, (other variables));

my $name = $0;
$name =~ s~.*/~~;
my ($verb, $object) = split /-/, $name;

$action = $verb;

# Case statement for defaults for verb.

# Case statement for defaults for object.

# Case statement for defaults for name (combines verb + object)

GetOptions(
    "action=s" => \$action,
    "type=s" => \$type,
    "foo=i" => \$foo,
    ...
);

and more program
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If you're using Perl 5.10 or better you can use feature "switch"; at the beginning and then:

given($object) {
    when ("tap") {$type = "domestic"}
    ....
}
[download]