Use a script to take two numbers as arguments and output their sum using (i) bc (ii) expr. include error - checking to test whether two arguments were entered?

If I understand correctly your question, You want to pass 2 parameters to shell script and print the sum of those. Also, you want to throw error if the number of parametrs are less than 2.



Hope this helps...

#!/bin/ksh

while echo " Enter two numbers :\n " ; do
echo "Enter num 1: "; read A;
echo "Enter num 2: "; read B;
if [ -z $A -o -z $B ] ;then
echo " Invalid input , pls enter again"
else
break
fi
done

export A B

echo " ************* MENU *********** \n"
echo " 1. cal using bc ";
echo " 2. cal using expr";
echo " enter you choice :";
read c;

case $c in
1) sum=`echo " $A + $B "|bc` ;;
2) sum=`expr $A + $B` ;;
*) echo "invalid option , run script again"
esac

if [ $? -eq 0 ]
then echo " Sum is $sum"
else
echo " Script failed "
fi