Question

I was writing a script to check if a number is Armstrong or not. This is my Code

echo "Enter Number"
read num
sum=0
item=$num
while [ $item -ne 0 ]
do
rem='expr $item % 10'
cube='expr $rem \* $rem \* $rem'
sum='expr $sum + $cube'
item='expr $item / 10'
done
if [ $sum -eq $num ]
then
echo "$num is an Amstrong Number"
else
echo "$num is not an Amstrong Number"
fi

After I run this script,

$ ./arm.sh

I always get these errors

line 5: [: too many arguments

line 12: [: too many arguments

I am on cygwin.

Answer 1

Those are straight quotes in your expr commands. To evaluate an expression, you need to use backquotes:

rem=`expr $item % 10`