Copy keys from one Redis instance to another

redis-copy.sh

# Set variables accordingly
source_host=ecfoo.amazonaws.com
source_password=foo
source_port=6666
source_db=0
target_host=ecbar.amazonaws.com
target_password=bar
target_port=6777
target_db=0

redis-cli -h $source_host -a $source_password -p $source_port -n $source_db keys \* | while read key; do 
  echo "Copying $key"; 
  redis-cli --raw -h $source_host -a $source_password -p $source_port -n $source_db DUMP "$key" | head -c -1|redis-cli -x -h $target_host -a $target_password -p $target_port -n $target_db RESTORE "$key" 0;
done

Don't use KEYS, use SCAN instead (or the cli's --scan switch).