Atomically delete keys matching a pattern in Redis

redis-delete.sh

###################################################################
#Script Name	: redis-delete                                                                                            
#Description	: Given a host, port and pattern to delete from Redis. Example ./redis-delete.sh redis-XXXX.XXXX.com 6379 stage:*                                                                          
#Args         : <host> <port> <pattern>                                                                                  
#Author       : Dimitry Kudryavtsev                                               
#Email        : dimitry@mentful.com                                           
###################################################################

if [ $# -ne 3 ] 
then
  echo "Delete keys from Redis matching a pattern using SCAN & DEL"
  echo "Usage: $0 <host> <port> <pattern>"
  exit 1
fi

cursor=-1
keys=""

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

  reply=`redis-cli -h $1 -p $2 SCAN $cursor MATCH $3`
  cursor=`expr "$reply" : '\([0-9]*[0-9 ]\)'`
  if [[ $reply = *[[:space:]]* ]]
  then
    keys=${reply#[0-9]*[[:space:]]}
    for key in $keys; do
      echo "Delete the following key: $key"
      redis-cli -h $1 -p $2 DEL $key 
    done
  fi
done