That might be useful if you want floating point math, but most shell scripts can just use the integer math in shell: $ x=10 $ echo $((x - 1)) 9 Th

That might be useful if you want floating point math, but most shell scripts can just use the integer math in shell: $ x=10 $ echo $((x - 1)) 9 Though if I need to do a floating point calculation at the shell, I start python or R, which both have their own interactive shells (with the same readline interface, which I like).