[syslinux] What extlinux -M does?

[Regid Ichira]

  1. Which label is referred by

    -M, --menu-save=label
              Set the label to select as default on the next boot
?

  2. With

    # grep 'label' /boot/extlinux/extlinux.conf
    label 1
         menu label An old linux version

2.1 What will be the consequences of
    # extlinux -M 1 /boot/extlinux
and
    # extlinux -M 'An old linux version' /boot/extlinux

2.2 What are the differences between
    # extlinux -M 'An old linux version' /boot/extlinux
and
    # extlinux -o 1 /boot/extlinux
?