A bash script that scans Redis keys by pattern using SCAN

redis-scan.sh

#!/usr/bin/env bash
# redis-scan.sh
#
# Adapted by @obscurerichard from itamarhaber/scan_del.sh:
#     https://gist.github.com/itamarhaber/11126830
#
# Thanks @czerasz and @tenlee2012 for fixes
#
# Usage:
#      ./redis-scan.sh localhost 6378 0 '*test*'
#
# NOTE: if your redis-cli supports '--scan' use that instead, thanks @ferico
#
#     redis-cli --scan --pattern '*'
#

if [ "$#" -lt 2 ]
then
  echo "Scan keys in Redis matching a pattern using SCAN (safe version of KEYS)"
  echo "Usage: $0 <host> [port] [database] [pattern]"
  exit 1
fi
host=${1:-}
port=${2:-6379}
database=${3:-0}
pattern=${4:-\*}
cursor=-1
keys=""

echo "host=${host},port=${port},database=${database}"
while [[ "$cursor" -ne 0 ]]; do
  if [[ "$cursor" -eq -1 ]]
  then
    cursor=0
  fi

  reply=$(redis-cli -h "$host" -p "$port" -n "$database" SCAN "$cursor" MATCH "$pattern")
  cursor=$(expr "$reply" : '\([0-9]*[0-9 ]\)')
  keys=${reply//$cursor/}
  if [ -n "$keys" ]; then
    echo "$keys"
  fi
done

Tried many modifications and it seems only scan is working and delete is not properly executed. After rescan the keys still existing

redis-cli -h xxxxxx -a 'xxxxxx' -n 0 -p 6379 --scan --pattern 'xxxxxx*' | xargs -L 2000 redis-cli -h xxxxxx -a 'xxxxxx' -n 0 -p 6379 del