use vars qw($opt_d $opt_x $opt_h);
use Getopt::Std;
#
&getopts("a::d::h")||die "ERROR: No such option. -h for help\n";
&help if ($opt_h);

if ($opt_a){
    printf("not implemented.");
}elsif ($opt_d){
$base = shift(@ARGV);
$base2= shift(@ARGV);

  print $base;
  print $base2;
etc.
_______________________________________________

#!/usr/bin/perl

use strict;
use warnings;
use Getopt::Long;

GetOptions('-d' => \my $d_schalter);

my @files = @ARGV;
print $_,"\n" for @files;

#!/usr/bin/perl

use strict;
use warnings;
use Getopt::Long;

use vars qw($opt_d $opt_a $opt_h);

#
GetOptions("-a" => \$opt_a,
              "-d"  => \$opt_d,
              "-h"  => \$opt_h,);

help() if ($opt_h);

if ($opt_a){
   print "not implemented.";
}
elsif ($opt_d){
   my $base = shift(@ARGV);
   my $base2= shift(@ARGV);

    print $base;
    print $base2;
}

#!/usr/bin/perl

use strict;
use warnings;
use Getopt::Long;

use vars qw($opt_d $opt_a $opt_h $argument);

#
GetOptions("-a" => \$opt_a,
              "-d"  => \$opt_d,
              "-s=s" => \$argument,
              "-h"  => \$opt_h,);

help() if ($opt_h);

if ($opt_a){
   print "not implemented.";
}
elsif ($opt_d){
   my $base = shift(@ARGV);
   my $base2= shift(@ARGV);

    print $base;
    print $base2;
}

if(defined $argument){
   print $argument;
}

#!/usr/bin/perl

use strict;
use warnings;
use Getopt::Long;

my (@files,$opt_a,$opt_h);

#
GetOptions("-a" => \$opt_a,
             "-d"  => \@files,
             "-h"  => \$opt_h,);

help() if ($opt_h);

if ($opt_a){
  print "not implemented.";
}
elsif ($opt_d){
   print $_,"\n" for(@files);
}

#!/usr/bin/perl

use strict;
use warnings;
use Getopt::Long;

my (@files,$opt_a,$opt_h);

#
GetOptions("-a" => \$opt_a,
            "-d"  => \@files,
            "-h"  => \$opt_h,);

help() if ($opt_h);

if ($opt_a){
    print "not implemented.";
}
if (@files){
    print $_,"\n" for(@files);
    die "Nicht genügend Dateien" if(scalar(@files) < 2);
}

sub help{
    print "help";
    exit;
}

#!/usr/bin/perl
use strict;
use warnings;
use Getopt::Long;

my ($opt_a, $opt_d);

# Optionen auswerten
GetOptions(
    a          => sub { die "noch nicht implementiert" },
    d          => \$opt_d,
    'h|help'    => \&help,
) or help();

# Restliche Argumente in @files
my @files = @ARGV;

# Wenn $opt_d, dann müssen zwei Argumente da sein!
die "zu wenig Argumente" if $opt_d && scalar @files < 2;
 
# und so weiter

sub help {
    print <<EOT;
Usage: ...
EOT
    exit -1;
}