Math

How to add numbers in bash ?

• Use arithmetic expansion: $((EXPR))

num=$((num1 + num2))
num=$(($num1 + $num2))        # Also works
num=$((num1 + 2 + 3))         # ...
num=$[num1+num2]              # Old, deprecated arithmetic expression syntax

• Ref: https://stackoverflow.com/a/6348941/4814427