#!/usr/bin/perl

use strict;
use warnings;
use Tk;

my $mw = Tk::MainWindow->new;
$mw->minsize( 300, 250 );

my $entered = "\x{171}";

open OUT, '>>', $entered;
binmode OUT, ":encoding(UTF-8)";

my $entry = $mw->Entry(
    -textvariable => \$entered,
    -width        => 75,
    -takefocus    => 1,
)->pack();
$entry->focus( -force );

my $go = sub {
    print OUT "$entered\n";
};

my $buttgo = $mw->Button(
    -text    => "Go",
    -command => $go
)->pack();

$mw->bind( '<Return>', $go );

my $buttexit = $mw->Button(
    -text    => "Exit",
    -command => sub { exit },
)->pack();

close OUT;

Tk::MainLoop();