Bash: Luhn help

Programming Bash
1

whats wrong with my script?

#!/usr/bin/env bash

declare input="$@"

[ "${#input}" -le 1 ] && { echo false; exit; }

input="${input// /}"

[[ "$input" =~ ^[0-9]+$ ]] || { echo false; exit; }

declare -i counter=0

declare -i sum=0

declare -i digit=0

while [ "$counter" -lt "${#input}" ]; do
        digit=${input:$counter:1}
        ((counter++%2 == 0)) && { ((digit+digit > 9)) && ((sum+=digit+digit-9)) || ((sum+=digit+digit)); } || \
        ((sum+=digit))
done

((sum%10 == 0)) && echo true || echo false

Locally I can pass most tests but when Im run testing in exercism Im failing 5 tests only about SIN. I followed all the instructions and examples in the question.

2
  1. How are you running the tests locally!?
  2. What failures are you seeing when you run the tests on the website? (Please don’t use images to show us.)