Please find the code snippet which I tried :

sub TabulateModules{
    
    print "TabulateModules\n";
    print "=================\n";
    my $paneModules = $_[0];
    my $Index = 0;
    my $ModuleButtonReference = 0;
    if (@ModuleButtonarray){
        foreach my $array (@ModuleButtonarray){
            $array->packForget();
        }
    }
    @ModuleButtonarray = ();
    @cbvalue = ();
    
    ###Debug : To remove
    @aModules = ("tt", "kl");
    unshift(@aModules, "Select all");

    foreach my $Modules (@aModules){
        $ModuleButtonReference = $paneModules->Checkbutton(
        -text     => "$Modules",
        -variable => \$cbvalue[$Index],
        -onvalue => 1,
        -offvalue => 0,
        -font => 'big',
        -foreground=>'black',
        -bg => 'DimGray',
        )->pack(-side=>'top',-anchor=>'sw' );
        $Index++;
        push(@ModuleButtonarray, $ModuleButtonReference);
    }
}
[download]

Please Note : The "paneModules" is a scrolled pane. Description : In this snippet, Im creating a list of check button. For selecting all the check button at one go, I added one more item to the list say "Select all". My query is : if the check button "Select all" is selected, all other check box should also get selected and I want the checked items in a list.How can this be done?