#! /usr/local/bin/perl -w use strict; use Tk; my $var2 = ''; my $w = new MainWindow; $w->Entry( -validate => 'all', -validatecommand => [ \&print_var, \$var2 ], -textvariable => \$var2 )->pack; MainLoop; sub print_var { my $var = shift; print scalar(localtime)," >$$var\n"; }