Script to send email on Debian based server at shutdown and restart.

email.sh

#!/bin/sh
### BEGIN INIT INFO
# Provides: SystemEmail
# Required-Start: $remote_fs $syslog
# Required-Stop: $remote_fs $syslog
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Short-Description: Send email
# Description: Sends an email at system start and shutdown
### END INIT INFO

EMAIL="example@example.com"
RESTARTSUBJECT="["`hostname`"] – System Startup"
SHUTDOWNSUBJECT="["`hostname`"] – System Shutdown"
RESTARTBODY="This is an automated message to notify you that "`hostname`" started successfully.

Start up Date and Time: "`date`
SHUTDOWNBODY="This is an automated message to notify you that "`hostname`" is shutting down.
Shutdown Date and Time: "`date`
LOCKFILE=/var/lock/SystemEmail
RETVAL=0

# Source function library.
. /lib/lsb/init-functions

stop()
{
   echo -n $"Sending Shutdown Email: "
   echo "${SHUTDOWNBODY}" | mail -s "${SHUTDOWNSUBJECT}" ${EMAIL}
   sleep 4
   RETVAL=$?

   sleep 4
   if [ ${RETVAL} -eq 0 ]; then
      rm -f ${LOCKFILE}
      sleep 4
      success
   else
      failure
   fi
   echo
   return ${RETVAL}
}

start()
{
   echo -n $"Sending Startup Email: "
   echo "${RESTARTBODY}" | mail -s "${RESTARTSUBJECT}" ${EMAIL}
   RETVAL=$?

   if [ ${RETVAL} -eq 0 ]; then
      touch ${LOCKFILE}
      success
   else
      failure
   fi
   echo
   return ${RETVAL}
}

case "$1" in
start)
start
;;
stop)
stop
;;
status)
echo "Not applied to service"
;;
restart)
stop
start
;;
reload)
echo "Not applied to service"
;;
condrestart)
#
echo "Not applied to service"
;;
probe)
;;
*)
echo "Usage: SystemEmail{start|stop|status|reload|restart[|probe]"
exit 1
;;

esac
exit ${RETVAL}

Then all you have to do is run the following commands as root (or elevate with sudo):

1. make it executable with chmod u+x email.sh
2. copy it to init.d with cp email.sh /etc/init.d/
3. make root have ownership of the file with chown root:root email.sh
4. set it to run automatically via update-rc.d email.sh start 98 2 3 4 5 . stop 02 0 1 6 .

If you want to remove the script you can do so by using sudo update-rc.d -f email.sh remove

You can also test that it is running after step 1 by running ./email.sh start and ./email.sh stop

success and failure are not default debian init-functions.
You might want to use log_success_msg / log_failure_msg.

suggestion:

      log_success_msg "Success sending startup mail: ${RETVAL}"
      log_failure_msg "FAIL: sending startup mail failed with: ${RETVAL}"