Recursive Fibonacci in Bash script

Question

This is my attempt:

#!/bin/bash

function fibonacci(){

first=$1
second=$2

if (( first <= second ))
then
return 1

else 

return $(fibonacci $((first-1))         


        

Answer 1

While calculating fibonacci numbers with recursion is certainly possible, it has a terrible performance. A real bad example of the use of recursion: For every (sub) fibonacci number, two more fibonacci numbers must be calculated.

A much faster, and simple approach uses iteration, as can be found here:

https://stackoverflow.com/a/56136909/1516636