#!/usr/bin/perl

use strict;
use warnings;

use Tk;

my $text;
my $mw = tkinit;
my $textw = $mw->Text()->pack;
$mw->Button( -command => \&getfilename, -text => 'oeffnen' )->pack;
$mw->Button( -command => \&getoutput, -text => 'speichern' )->pack;


MainLoop;

sub getfilename{
    my $file = $mw->getOpenFile;
    if( open my $fh, '<', $file ){
        local $/;
        $text = <$fh>;
    }
    $textw->insert('end', $text);
}

sub getoutput{
    my $file = $mw->getSaveFile;
    if( open my $fh, '>', $file ){
        $text = $textw->get('1.0','end');
        print $fh $text;
        close $fh;
    }
}