Brauche Hilfe bei Shutdownscript

andreas@andreas-server:~$ crontab -l
*/15 * * * * /usr/bin/checkidle.sh >> /var/log/checkidle.log


andreas@andreas-server:~$ cat /usr/bin/checkidle.sh
#!/bin/bash


#-------------------------------------------------------------------
# Got from: http://www.administrator.de/index.php?content=43744
#           http://www.vdr-portal.de/board/thread.php?threadid=97411
# and added the while loop
# and modified the login status
#-------------------------------------------------------------------
#
# */15 * * * * /home/andreas/bin/checkidle/checkidle.sh >> /home/andreas/bin/checkidle/checkidle.log
#


TIMEOUT=600                                                       # Set the Timeout
CLIENTS=`cat /etc/checkidle.conf`   # IPs of the clients
#TIME=`date "+%d.%h  %H:%M:%S"`
loop_active=1
while [ $loop_active -eq 1 ]
do


   echo "`date "+%d.%h  %H:%M:%S"`  Waiting $TIMEOUT seconds"
   sleep $TIMEOUT                               # Give me a timeout before loggin in and between loops...
   keep_alive=0                                 # Preset keep_alive FALSE


##### Check if a user is logged in. If true, then exit script without doing a shutdown


#CHECK=$(DISPLAY=:0 /usr/bin/gnome-screensaver-command -q)
#echo $CHECK | grep "inaktiv" #> /dev/null
#CHECK=$(DISPLAY=:0 /usr/bin/xscreensaver-command -time)
#echo $CHECK | grep "non-blanked" > /dev/null
#CHECK=$(DISPLAY=:0.0 /usr/bin/gnome-screensaver-command -t)
#echo $CHECK | grep "nicht aktiv" > /dev/null




#   if [ $? == 0 ] ; then                        # $login is != NULL
#     echo "`date "+%d.%h  %H:%M:%S"`  Someone is logged in, exit script"
#      keep_alive=1                              # Stay active since someone's logged in
#      loop_active=0                             # Will terminate the while loop
# else echo "Shutdown wenn kein Netzwerk aktiv ist."
#  fi


##### Check if a client is online. If true, then poll again later. If false exit script and shutdown


   for i in $CLIENTS                            # Loop thru the list of clients
   do
      ping -c 2 $i > /dev/null                  # Check if client is online
      if test $? -eq 0
      then
         keep_alive=1                           # Stay active but keep executing the while loop...
         echo "`date "+%d.%h  %H:%M:%S"`  $i can be pinged, exit script"
         exit
      fi
   done
   if test $keep_alive -eq 0                    # If no user and no client is online exit while loop
   then
      loop_active=0                             # Will terminate the while loop and probably shutdown the system...
   fi
done


if test $keep_alive -ne 1
then
   echo "`date "+%d.%h  %H:%M:%S"`  Computer will shutdown now..."
   sleep 10                                     # Shutdown after 10 seconds
   sudo /usr/sbin/pm-suspend    # Maybe replace with other shutdown commands
   exit
fi