Example of SCAN / COUNT looking for patterns in REDIS

find_in_redis.sh

#!/bin/bash

# sample code demonstrating a pattern search with SCAN
# using a COUNT "work intent"

if [ $# -ne 3 ]
then
  echo "Find matching a pattern using SCAN "
  echo "Usage: $0 <host> <port> <pattern>"
  exit 1
fi

cursor=-1
keys=""

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

  reply=`redis-cli -h $1 -p $2 SCAN $cursor COUNT 10000 MATCH $3`
  cursor=`expr "$reply" : '\([0-9]*[0-9 ]\)'`
  keys=${reply/$cursor/}

  if [[ $keys != "" ]]
  then
    echo "keys: $keys"
  fi
  loops=$(( loops + 1 ))
done
echo "loops : $loops"

This is incorrect solution. If keys, returned in reply, have substrings, equal to cursor, these keys will be corrupted by regex replacement on line 25.
It is better to use arrays:

set -a reply $(redis-cli -h $1 -p $2 SCAN $cursor COUNT 10000 MATCH $3)   # set -A in ksh
cursor=${reply[0]}
keys=${reply[@]:1}