#!/usr/bin/perl

use strict;
use Tk;

my $mw = MainWindow->new();

my $txtvar;  # have a separate scalar for each Entry widget

$mw->Entry(-textvariable=>\$txtvar # this is the trick
           )->pack();

$mw->Button(-text=>"Print & Clear",
            -command=>sub{print $txtvar,$/; $txtvar=""}
            )->pack();

MainLoop;

##</code><code>##

my %strings = qw/first one second two third three/;

for my $name ( sort keys %strings ) {
    $mw->Label(-text => $name)->pack();
    $mw->Entry(-textvariable => \$strings{$name})->pack();
}

$mw->Button(-text=>"Print&Clear",
            -command=>sub{ for (sort keys %strings) {
                              print "$_=$strings{$_} ";
                              $strings{$_} = "";
                           }
                           print $/;
                         }
            )->pack();