Shell Programming and Scripting

#!/bin/ksh
echo "SID must be in oratab file"
echo "Enter ORACLE_SID of Database:\c "
read ORACLE_SID
x=`cat /etc/oratab| grep $ORACLE_SID | wc -l`
for X in $x
do
        if [[ $X -eq 1 ]];then
                echo "SID FOUND"
        else
                echo "nothing found"
                echo "Enter valid SID"
                continue
        fi
done

#!/bin/ksh
echo "SID must be in oratab file"
echo "Enter ORACLE_SID of Database:\c "
read ORACLE_SID
while :
do
        if [[ $( grep -wc "$ORACLE_SID" /etc/oratab ) -ne 0 ]]
        then
                echo "SID Found"
                break;
        else
                echo "nothing found"
                echo "Enter valid SID"
                read ORACLE_SID
                continue;
        fi
done

if grep -q "$ORACLE_SID" /etc/oratab

if grep "$ORACLE_SID" /etc/oratab >/dev/null 2>&1