How to add values in a variable in Unix shell scripting?

Question

I have two variables called count1 and count7

count7=0
count7=$(($count7 + $count1))

This shows an error \"expression is not complete; more tok

Answer 1

I don't have a unix system under my hands, but try this:

count7=$((${count7} + ${count1}))

Or maybe you have a shell that doesn't support this expression. I think bash does support it, but sh doesn't.

EDIT: There is another syntax, try:

count7=`expr $count7 + $count1`