When Redis is configured to use an ACL file (with the aclfile configuration
option), this command will save the currently defined ACLs from the server memory to the ACL file.
*返回值
字符串: OK on success.
The command may fail with an error for several reasons: if the file cannot be written or if the server is not configured to use an external ACL file.
*例子
> ACL SAVE
+OK
> ACL SAVE
-ERR There was an error trying to save the ACLs. Please check the server logs for more information