If you want to print each fibonacci value from 1 to $n, I suggest:
fib_r() {
local i=$1
if (( i < 0 )); then
echo "Error: negative numbers not allowed" >&2
exit 1
elif (( i <= 1 )); then
echo 1$i
else
echo $(( $($FUNCNAME $((i - 1)) ) + $($FUNCNAME $((i - 2)) ) ))
fi
}
fib() {
local i
for (( i = 1; i <= $1; i++ )); do
fib_r $i
done
}
fib 10
outputs
0
1
1
2
3
5
8
13
21
34
It's still one variable, albeit one per function.
I use the bash variable $FUNCNAME in the recursive function so you don't have to hardcode the function name within itself. I got bit by not updating that line when I renamed the function.
Of course your performance will greatly improve if you cache the results: "fib 16" takes, on my VM, about 3.5 sec without caching and about 0.03 sec with caching.
fib_r() {
local i=$1
if (( i < 0 )); then
echo "Error: negative numbers not allowed" >&2
exit 1
elif [[ -n ${fib_cache[i]} ]]; then
echo "${fib_cache[i]}"
elif (( i <= 1 )); then
echo 1$i
else
echo $(( $( $FUNCNAME $((i - 1)) ) + $( $FUNCNAME $((i - 2)) ) ))
fi
}
fib_cache=()
fib() {
local i
for ((i=1; i<=$1; i++)); do
fib_cache[i]=$(fib_r $i)
echo "${fib_cache[i]}"
done
}