use Tk;
use strict; 
use warnings;

my $window = MainWindow -> new();
$window->geometry("520x580");

my $entry_frame = $window -> Frame()->pack(-side => "top");
my $entry = $entry_frame -> Entry (-width => 53, ) -> pack(-side => 'left'); 
$entry -> bind('<Return>'=> \&button_Click); 
$entry -> focus;

my $button = $entry_frame -> Button (-text => "Search", -command => \&button_Click ) -> pack (-side => 'right');
my $display_field = $window -> Scrolled("Text",-scrollbars => 'e', ) -> pack(-side => 'top',-fill => 'y', -expand => 1); 

sub button_Click {
	my $now = time;
	my $file = "./data"; #text file about the size of 30 MB
	open my $data, '<', $file or die "Open failed: $!"; 
    $display_field->delete('0.0','end');
	my $query = $entry->get();	
	
	while (<$data>) {			
			if(/$query/i){
				$display_field->insert("end",$_);
				$window->update;				
			}
			
		}	
		$now = time - $now;
		my $time = sprintf("\n\nTotal running time: %02d:%02d:%02d\n\n", int($now / 3600),
            int(($now % 3600) / 60), int($now % 60));
		$display_field->insert('end',$time);	
}

MainLoop;