My code skeleton looks like:

my $window = Tk::MainWindow->new();
my $book = $window->NoteBook();

#geometry, pack, title etc

@input=("corner1","corner2")#generated by another loop

#other buttons frames etc

foreach my $corner (@input) {
$tab = $book->add("TAB $index", -label => "$corner");
$for_display=$tab->Scrolled('Text', )->pack();
#blah blah
$CHILD = IO::Handle->new;
open($CHILD, "$unix_command 2>&1 |");
$logWindow->fileevent($CHILD, 'readable', [\&callback,args]);
}

#then using sub callback will insert the $_ if sysread.