#!/bin/bash

digits=(0 1 2)
max=2

permute() {
	local d="" pad=""
	for d in "${digits[@]}"; do if ((${#1} < max)); then
		pad="$1$d"
		if ((${#pad} == max)); then
			echo "$pad"
		else
			permute "$pad"
		fi
	fi
        done
}

permute