Shell Programming and Scripting

LOCK1=$TRANSOUT/lock1.txt             # name and place of first lockfile
LOCK2=$TRANSOUT/lock2.txt             # name and place of second lockfile
HEARTBEATFILE=$TRANSOUT/heartbeat       # name and place of heartbeat file for
while :                                          # start an infinite loop here
 do
    LOGFILE=`date +$LOGDIR/COPY_LOG_%Y%m%d.log` # name and place of our daily logfile
    HEARTBEAT=`date +%Y%m%d%H%M`                 # heartbeat timestamp
    TIMESTAMP="`date +%H:%M:%S`"                 # timestamp to add to our log
    
    typeset -i count                             # declare the count variable to be local to the function it is defined in
    rm -f $LOCK1                              # remove our lockfile if we didn't exit cleanly              
    
     while [ -f $LOCK2 ]                      # while Others are busy
      do
    
          unset TIMESTAMP                        # clear timestamp so we will see the right time for the next log entry
          sleep 10                               # wait for 10 seconds and retry
          TIMESTAMP="`date +%H:%M:%S`"           # new timestamp to add to our log
          count=$((count + 1))                   # increment counter by one
    
           if [ $count -eq 12 ] ; then           # if we waited 120 seconds
           
            echo "Lockfile present" | mailx -m -s "WARNING LOCKFILE PRESENT, WAITED 120 SECONDS" john@doe.com # email the culprit
            echo "$LOCK2 PRESENT, WAITED 120 SECONDS" | sed -e 's/^/'"$TIMESTAMP"' /g' >> $LOGFILE # add message to logfile
           
            count=0                              # restart the counter
           fi
      done                                       # if no second lockfile exists (anymore)
                             
     echo $$ > $LOCK1                         # create our own lockfile with our own process ID so that others know we are working
                                                 
     cd /interface          # go to initial directory where files are
   
     ls -1 * > move.lst                      # (ONE not L!) create a list of file names in single column format in directory
                                                 # and put them into one file called move.lst
                                
      if [ -s move.lst ] ; then              # check to see if move.lst is not empty so we can continue

       while read N                              # while we read lines in move.lst
        do
         case
           *) echo >>run_move.lst mv $N $TRANSOUT/ ;;                # add move command and put this in run_move.lst
          esac
        done <move.lst

       chmod 777 run_move.lst                   # make run_move.lst executable
       run_move.lst                             # and execute it
                                                 
       rm move.lst                           # remove original list
       cat run_move.lst | sed -e 's/^/'"$TIMESTAMP"' /g' >> $LOGFILE # add our move list to a logfile
       rm run_move.lst                          # remove move list

      else                                       # if move.lst is empty in the first place
       echo "NO FILES TO MOVE" | sed -e 's/^/'"$TIMESTAMP"' /g' >> $LOGFILE # add a message to the logfile
       rm move.lst                           # remove original list
      fi

    COPYFILE="meert.log"
    cp $LOCK1 $LOGDIR/$COPYFILE               # put the current process id to the logdir
    echo $HEARTBEAT > $HEARTBEATFILE             # put heartbeat timestamp into heartbeat file
    rm -f $LOCK1                              # remove our lockfile so the next program can start
                                                 
    unset TIMESTAMP                              # clear timestamp so we will see the right time for the next log entry
    sleep 180                                    # wait another 180 seconds and start with the whole process again
    TIMESTAMP="`date +%H:%M:%S`"                 # new timestamp to add to our log
    echo "WAITED 180 SECONDS FOR NEXT MOVE" | sed -e 's/^/'"$TIMESTAMP"' /g' >> $LOGFILE # add a message to the logfile
    unset TIMESTAMP                              # clear timestamp so we will see the right time for the next log entry
    unset HEARTBEAT                              # clear heartbeat timestamp
    unset LOGFILE                                # clear logfile name so this program keeps logging to the most current logfile
 done

count=0
while [ -f $LOCK2 ]                      # while Others are busy
do
  if [ $count -eq 12 ] ; then            # if we waited 120 seconds
    TIMESTAMP="$(date +%H:%M:%S)"        # new timestamp to add to our log

    echo "Lockfile present" | .......
    echo "$LOCK2 PRESENT, WAITED 120 SECONDS" | .......

    count=0
  fi
  sleep 10                               # wait for 10 seconds and retry
  count=$((count + 1))                   # increment counter by one
done

while [ 1 ];do
   mv  $COMMON  $PRIVATE
   if [ $? -eq 0  ];then 
      # critical section here
      # do the work and   release the lock 
      mv $PRIVATE  $COMMON
   else 
       #  bad luck 
       sleep 120
    fi
done