UNIX for Dummies Questions & Answers

#!/bin/ksh
tail /var/adm/messages > new_alert.tmp
while true
do
diff new_alert.tmp last_alert.tmp
if [ $? -eq 0 ]
then
        echo No new alert messages `date`
        sleep 15
else
        continue
fi
done
exit

changed="NO"

while [ $changed == "NO" ]; then
do
  echo $FIELDS > new_alert.tmp
  diff new_alert.tmp last_alert.tmp
  if [ $? -eq 0 ]; then
    echo No new alert messsages `date`
    sleep 15
    changed="YES"
  else
    continue
  fi
done

while [ 1 = 1 ]
do 

clear

integer EXT=1
ALERTDIR=/var/opt/projects/mnp/logs/alerts
CURRENTLOG=$ALERTDIR/alert.log.$EXT

# Moving on until a file is found
until [  -s $CURRENTLOG ] 
do
        EXT=`expr $EXT + 1`     
        CURRENTLOG=$ALERTDIR/alert.log.$EXT
done


# Makes the substitution of the fields in the alert logs.
FIELDS=`cat $CURRENTLOG | sed -e 's/">/, /g' \
             -e 's/<\/OBJECT>/, /g'  \
             -e 's/<//g'`

echo $FIELDS > new_alert.tmp

diff new_alert.tmp last_alert.tmp
        if [ $? -eq 0 ]
        then 
                echo No new alert messsages `date`
                sleep 15 
                ???????;
        else
                continue;
        fi

CODE=`echo $FIELDS | cut -f2 -d,`
DATE=`echo $FIELDS | cut -f4 -d,`


if [ $CODE = "T004" ]
then
        echo $FIELDS | cut -f2,4,12,15,17 -d, \
        \
        | awk -F"," '{print  ""; \
        print "ALERT ID   :" $1; \
        print "TIMESTAMP  :" $2; \
        print "ERROR CODE :" $3; \
        print "MSISDN     :" $4; \
        print "ERROR      :" $5}'

elif [ $CODE = "T002" ]
then
        echo $FIELDS | cut -f2,4,12,15,17 -d, \
        \
        | awk -F"," '{print ""; \
        print "ALERT ID   :" $1; \
        print "TIMESTAMP  :" $2; \
        print "ERROR CODE :" $3; \
        print "MSISDN     :" $4; \
        print "ERROR      :" $5}'

else 
        echo $FIELDS | cut -f2, -d, \
        \
        | awk -F"," '{print  ""; \
        print "ALERT ID   :" $1}' 
        echo "Unknown ERROR type, check with 3rd line"
fi

echo File `basename $CURRENTLOG`

cp new_alert.tmp last_alert.tmp
sleep 5
done