How to run a script at shutdown

Question

I want to reset the hardware clock from the system clock at shutdown. I created this script (K99savetime.sh):

#! /bin/sh
### BEGIN INIT INFO
# Provides:         savetime.sh
# Default-Start:    6 0
# Short-Description: set hwclock.
# Description:  set hwclock to systemclock on halt or reboot.
### END INIT INFO

PATH=/sbin:/usr/sbin:/bin:/usr/bin

log_action_msg "Updating hwclock with system clock"
hwclock --systohc
exit 0

I saved the script to /init.d, made it executable, and created a symbolic link in /etc/rc6.d

The machine appears to shutdown correctly, that is, I don't see any errors and it doesn't hang up.

1. How do I know that the script runs at shutdown?

2. Is the script correctly written to do what I want?

Answer 1

To make the script run at both shutdown and restart symbolic links must be created in both /etc/rc0.d and /etc/rc6.d. The link file should be the same name as the script but with S10 prepended to the script name so that it will run early. I used "touch" to create a file just before the hwclock command and just after. It appears to work but I don't understand all the options available in the INIT section of the script. –