#!/usr/bin/perl

use strict;
use warnings;
use utf8;

my %german_chars = (
  'Ä' => 'Ae', 'Ö' => 'Oe', 'Ü' => 'Ue', 'ä' => 'ae',
  'ö' => 'oe', 'ü' => 'ue', 'ß' => 'ss'
);

#For each argument apply the conversions selected
for my $old_name (@ARGV) {
  my $new_name = do_german($old_name);
  print "Old name: '$old_name'\nNew name: '$new_name'\n";
}

#Replace German characters with their ASCII equivalent
sub do_german {
  my $string = shift;  
  #Replace all German characters in the given string
  my @string_array = split //, $string;
  foreach (@string_array) {
    print "###Before replacement### $_\n";
    $_ = $german_chars{$_} if $german_chars{$_};
    print "###After replacement ### $_\n";
  }
  $string = join '',@string_array;
  return $string;
}

##</code><code>##

./test.pl für_elise
###Before replacement### f
###After replacement ### f
###Before replacement### &#65533;
###After replacement ### &#65533;
###Before replacement### &#65533;
###After replacement ### &#65533;
###Before replacement### r
###After replacement ### r
###Before replacement### _
###After replacement ### _
###Before replacement### e
###After replacement ### e
###Before replacement### l
###After replacement ### l
###Before replacement### i
###After replacement ### i
###Before replacement### s
###After replacement ### s
###Before replacement### e
###After replacement ### e
Old name: 'für_elise'
New name: 'für_elise'