#!/usr/bin/perl use warnings; use strict; use Tk; my $mw = Tk::MainWindow->new(); my $btn = $mw->Button(-text => "Click to close", -command => sub { closeWindow($mw); } ); $btn->pack(-padx => 10, -pady => 10); Tk::MainLoop(); sub closeWindow { my $mw = shift; $mw->destroy(); }