Assumes you have files junk{1,2,3}.dat in the current directory.

use Tk;

my $mw = new MainWindow();
my $content;
my $text = $mw->Text()->pack();
$text->Insert( "junk1.dat\njunk2.dat\njunk3.dat\n" );
my $ok = $mw->Button(
    -text => "View in Notepad",
    -command => sub{
        my $file = $text->getSelected;
        system 1, "notepad $file";
    }
)->pack();
MainLoop;
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