A bash script that scans Redis keys by pattern using SCAN

redis-scan.sh

#!/bin/bash

if [ "$#" -lt 1 ]
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

while [[ "$cursor" -ne 0 ]]; do
  if [[ "$cursor" -eq -1 ]]
  then
    cursor=0
  fi

  reply=$(redis-cli -h "$host" -p "$port" -n "$database" --raw SCAN "$cursor" MATCH "$pattern" COUNT 1000)
  cursor=${reply%%$'\n'*}
  if [[ "$cursor" != "$reply" ]]
  then
    echo "${reply#*$'\n'}"
  fi
done