foreach my $button ( @buttons ) {
   .........
   ........
   
    # Add a button widget
    $frame->Button(
        -anchor  => 'nw',
        -text    => "change " . $button,
        -command => [\&print_button_label, $button],
    )->pack( -side => 'left', -anchor => 'w', -padx => 2 );
}

###############################################
sub print_button_label{
    my $button = shift;
    print "button\n";
}


##</code><code>##

-command => sub { print_button_label( $button ) },