#! /bin/bash
#
#  fibonacci - Shell script for printing out Fibonacci Numbers
#
#---------------------------------------------------------------------------------
#
#  The Fibonacci sequence is 1, 1, 2, 3, 5, 8, 13, 21, ...
#
#  Defined by:
#      Fib(1) = 1 , Fib(2) = 1 , Fib(N) = Fib(N-1) + Fib(N-2) for all N >= 3. 
# 
#
#---------------------------------------------------------------------------------
#
#  Written by Todd Lisonbee 
#
#  Version: 0.1
#
#  This is a mostly useless script that I wrote to help me learn Bash Scripting.
#  On my computer overflow occurs after the 46th Fibonacci Number.
#
#		

usage="Usage: fibonacci [-v] [number of fibonacci numbers to print]"

if [ -z "$1" ]; then
	echo "$usage"
	exit 1

elif [ -n "$(echo $1 | grep '^-')" ]; then
	while getopts "vh" opt; 
	do
		case $opt in 
			v  ) 	echo "Fibonacci script version 0.1" 
				echo "Written by Todd Lisonbee"
				;;
			h )     echo "Here is some help" 
				echo "$usage"
				;;

			\? ) 	echo "$usage" 
				exit 1 ;;
		esac
	done
else
	first=1
	second=1
	count=2
	
	if (( $1 >=1 ));
	then
		echo $first
	else
		return
	fi

	if (( $1 >= 2 ));
	then
		echo $second
	else
		return
	fi

	while [ $count -lt $1 ];
	do
		current=$(($first+$second))
		echo $current
		first=$second
		second=$current
		count=$(($count+1))
	done
fi