shell script to find prime number

echo "Enter the limit : "

read no

i=2

while [ $i -le $no ]

do

j=1

flag=0

while [ $j -le $i ]

do

 m=`expr $i % $j`

 if [ $m -eq 0 ]

 then

 flag=`expr $flag + 1`

if [ $flag -gt 2 ]

then

break

fi

fi

 j=`expr $j + 1`

done

 if [ $flag -eq 2 ]

 then

 echo $i

 fi

i=`expr $i + 1`

done