#!/usr/bin/sh
# Copyright 2005 Daniel Cer (daniel.cer@cs.colorado.edu)
#
# This work is licensed under the Creative Commons Attribution-NonCommercial-
# ShareAlike License. To view a copy of this license, visit 
# http://creativecommons.org/licenses/by-nc-sa/2.5/ or send a letter to 
# Creative Commons, 543 Howard Street, 5th Floor, San Francisco, California, 
# 94105, USA.

function fibonacci {
   if [ $1 -le 0 ]; then fibonacci_ret=-1; return; fi
   if [ $1 -le 2 ]; then fibonacci_ret=1; return; fi
   fibonacci $[$1-1]
   local fib_n_sub1=$fibonacci_ret
   fibonacci $[$1-2]
   local fib_n_sub2=$fibonacci_ret
   fibonacci_ret=$[$fib_n_sub1 + $fib_n_sub2]  
}

if [ $# -ne 1 ]; then
  echo -e "Usage:\n\t$0 (n-th fibonacci # to calculate)"
  exit -1
fi

fibonacci $1
echo "fibonacci($1): $fibonacci_ret"