shell script to accept a number from the user and display all prime numbers till the number user enters.

Code:
echo Enter limit
read limit
j=1
flag=1
echo "Prime Number Series"
while [ $j -le $limit ]
do
    i=2
    while [ $i -lt $j ]
    do
         temp=`expr $j % $i`
         if [ $temp -eq 0 ]
         then
               flag=0
               break;
         else
               flag=1
         fi
         i=`expr $i + 1`   
    done
    if test $flag -eq 1
    then
          echo $j
    fi
    j=`expr $j + 1`
done

Output:
Enter limit
15
Prime Number Series
1
2
3
5
7
11
13