If I understand what you want to do correctly, the Tk::ExecuteCommand module should do it easily. There are other things you could do too, like embed a real xterm into the frame.

#!/usr/bin/perl
use Tk;
use Tk::ExecuteCommand;

my $mw = MainWindow->new;
$ec = $mw->ExecuteCommand(
    -command    => '',
    -entryWidth => 50,
    -height     => 10,
    -label      => '',
    -text       => 'Execute',
)->pack;
$ec->configure( -command => 'dir' );
$ec->execute_command;
$ec->bell;
$ec->update;

MainLoop;
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