Shell Programming and Scripting

 
#!/bin/sh
label:
echo sql poll
 v=`sqlplus -s <<!
 HR/HR
 set pages 0 echo off feed off
 select distinct status from
 emp
 where
 id=5;
 !
 `
echo $v;
echo it comes here after false
if [ "$v" -eq 4 ]
then
echo if condition true
sqlplus -l scott/tiger <<EOF
select * from department;
EXIT
EOF
else
   sleep 30;
   goto label
fi

 
#!/bin/sh
start(){
echo sql poll
 v=`sqlplus -s <<!
 HR/HR
 set pages 0 echo off feed off
 select distinct status from
 emp
 where
 id=5;
 !
 `
echo $v;
}
rval=start
if [ "$rval" -eq 4 ]
then
echo if condition true
sqlplus -l scott/tiger <<EOF
select * from department;
EXIT
EOF
else
   sleep 30;
   start
fi

start() {
.....
}

while :
do
  rval=`start`
  if [ "$rval" -eq 4 ]
  then
    echo if condition true
    sqlplus -l scott/tiger <<EOF
    select * from department;
    EXIT
EOF
    break
  else
     sleep 30
  fi
done