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If the shutdown was initiated successfully, WuInstall exits with code 5, otherwise it displays an error code and exits with code 6.
/reboot_message [message]
Displays the given message in the reboot dialog.
Use this option to show a custom message, the default message is "WuInstall reboot".
/shutdown_message [message]
Displays the given message in the reboot dialog.
Use this option to show a custom message, the default message is "WuInstall shutdown".