<<<<< TERMINAL SCREEN DRAWING SUBROUTINE >>>>>>>>

UTERMINAL

                    TERMINAL                  

NEXT

 $V1$

NEXT3

 $PROMPT$

     <<<<<< TIME POSE SUBROUTINE >>>>>>>>>

PAUSE

If they want to quit, do so

PAGETURNER

If they want to quit, do so

    <<<<<< 4 BOTTOM LINES CLEANING SUBROUTINE >>>>>>

ENCORE5

    <<<<<< REVIEW CLEANING SUBROUTINE >>>>>>

ENCORE

    <<<<<< CLEAN THE INSIDE OF BOUNDED ARE ONLY >>>>>

BOX

                          FILE                         

GO

 shutdown

 SYNTAX

       /etc/shutdown

 FUNCTION

       shutdown is the shell script for a graceful

       automated system shutdown.

       The actions of shutdown are practically the

       reverse of /etc/rc.  The shutdown

       process transfers the machine from the multi-user

       to the single-user mode.  Among many chores

       the principal ones for shutdown are:

          1. Warning users of an impending system shutdown.

          2. Killing off daemon tasks.

          3. Sync(ing) and halting the processor.

          4. Unmounting the file systems.

 Let us look at some entries in an /etc/shutdown file.

 # Bring the system down gracefully and ruthlessly.

 #  Read in minutes till shutdown.

 echo "Minutes till shutdown? (0-15):  "

 read num

 sleeptime=`expr $num \* 60`  # seconds

 echo "UNIX will shutdown in $num $min." | wall

 echo "Please finish and log off." | wall

 sleep $sleeptime    # Grace period   

 echo "All User Processes Now will be killed"

 killall    # kill all non-shutdown processes

 sync

 echo " Unmounting the file systems"

 /etc/umount /dev/rgb0e  2>/dev/null

 echo "Entering Single User Mode"

 init s

 Lines:

 read num  and  sleeptime=`expr $num \* 60` 

 obtain and set the grace period.

 # Bring the system down gracefully and ruthlessly.

 #  Read in minutes till shutdown.

 echo "Minutes till shutdown? (0-15):  "

 read num

 sleeptime=`expr $num \* 60`  # seconds

 The line:     sleep $sleeptime

 is the actual grace period being exercised

 # Bring the system down gracefully and ruthlessly.

 #  Read in minutes till shutdown.

 echo "Minutes till shutdown? (0-15):  "

 read num

 sleeptime=`expr $num \* 60`  # seconds

 echo "UNIX will shutdown in $num $min. "

 echo "Please finish and log off."

 sleep $sleeptime   # Grace period      

 The line:    killall

 will kill all outstanding processes (after

 the grace period has expired)

 # Bring the system down gracefully and ruthlessly.

 #  Read in minutes till shutdown.

 echo "Minutes till shutdown? (0-15):  "

 read num

 sleeptime=`expr $num \* 60`  # seconds

 echo "UNIX will shutdown in $num $min." | wall

 echo "Please finish and log off." | wall

 sleep $sleeptime    # Grace period   

 echo "All User Processes Now will be killed"

 killall    # kill all non-shutdown processes

 The line:     sync

 flushes the outstanding I/O buffers to disk.

 # Bring the system down gracefully and ruthlessly.

 #  Read in minutes till shutdown.

 echo "Minutes till shutdown? (0-15):  "

 read num

 sleeptime=`expr $num \* 60`  # seconds

 echo "UNIX will shutdown in $num $min." | wall

 echo "Please finish and log off." | wall

 sleep $sleeptime    # Grace period   

 echo "All User Processes Now will be killed"

 killall    # kill all non-shutdown processes

 sync

 The line:     /etc/umount /dev/rgb0e

 unmounts the file system /dev/rgb0e and sends

 all diagnostics to /dev/null.

 # Bring the system down gracefully and ruthlessly.

 #  Read in minutes till shutdown.

 echo "Minutes till shutdown? (0-15):  "

 read num

 sleeptime=`expr $num \* 60`  # seconds

 echo "UNIX will shutdown in $num $min." | wall

 echo "Please finish and log off." | wall

 sleep $sleeptime    # Grace period   

 echo "All User Processes Now will be killed"

 killall    # kill all non-shutdown processes

 sync

 echo " Unmounting the file systems"

 /etc/umount /dev/rgb0e  2>/dev/null

 The line:     init s

 changes the system level to single-user mode

 in which the power may be turned off.

 # Bring the system down gracefully and ruthlessly.

 #  Read in minutes till shutdown.

 echo "Minutes till shutdown? (0-15):  "

 read num

 sleeptime=`expr $num \* 60`  # seconds

 echo "UNIX will shutdown in $num $min." | wall

 echo "Please finish and log off." | wall

 sleep $sleeptime    # Grace period   

 echo "All User Processes Now will be killed"

 killall    # kill all non-shutdown processes

 sync

 echo " Unmounting the file systems"

 /etc/umount /dev/rgb0e  2>/dev/null

 echo "Entering Single User Mode"

 init s 

 If during the shutdown process you wanted the system

 administrator to reaffirm his or her intention to shutdown, 

 the if statement to place in the /etc/shutdown file

 would be:

??? this is too hard to understand and out of the blue

 $PROMPT$read yn      # read reply

 then

 if  

 That is correct!

 You've got it on the 2nd try.

 Good, you understand the concept.

 No, try test ...  or  [ "$yn" = ..]

 No, try test "..." = "y" ...  or  [ "$yn" = ...]

 You will be helped this time.

FORGET1

 if [ "$yn" = "y" ]                      

 Observe the result on the terminal.

 $PROMPT$