how can I sync folder using megatools copy?

Subject: how can I sync folder using megatools copy?

From: MisteryMonster

Date: Thu, 16 Jun 2022 12:37:47 +0800

I use "megatools copy -l backup_dir -r remote_dir" can only upload but 
not synchronize the folder, files removed in backup dir doesn't effect 
remote dir. So how can I sync the folder?