BASH base 62 encode / decode

base62.sh

#!/usr/bin/env bash

# https://gist.github.com/BobbyRyterski/7a511b96ece47655b17d
# based on http://stackoverflow.com/q/14471692

readonly BASE62=($(echo {0..9} {a..z} {A..Z}))

base62_encode() {
  local out=
  for i in $(bc <<< "obase=62; $1"); do
      out="${out}${BASE62[$((10#$i))]}"
  done
  echo $out
}

base62_decode() {
  echo $((62#$1))
}