1.shell script to print prime numbers up to a given range using arguments

echo " PRIME NUMBERS"

echo " **************" 

if [ $# -gt 2 -o $# -eq 0 ]

then

    echo -n "Enter 2 input to test: "

    read num1 num2

else

    num1=$1

    num2=$2

fi

case $num1 in

   *[!0-9]*)echo "Invalid input "

                                echo " ERROR!!"

      exit

      ;;

   *)break

      ;;

esac

case $num2 in

   *[!0-9]*)echo "Invalid input "

                                echo " ERROR!!"

      exit

      ;;

   *)break

      ;;

esac

echo " The Prime Numbers between $num1 to $num2  ARe:"

while [ $num1 -le $num2 ]

do

   i=2

   while [ $i -lt $num1 ]

   do

      if [ `expr $num1 % $i` -eq 0 ]

      then

         break

      fi

      i=`expr $i + 1`

   done

               

   if [ `expr $num1 / $i` -eq 1 ]

   then

      echo "$num1"

   fi

   num1=`expr $num1 + 1`

done