I have the following command:lftp -e 'mirror -R /local/backups /' -u username,password ftp://FTP_SERVERthis works fine, until I started cleaning the /local/backups folder. I'd like to upload new files to my FTP_SERVER without deleting those which don't exist locally anymore.I've tried the additional flags:--only-missing--only-newerbut neither is working. Is it at all possible? I know rsync has such an option, but that doesn't work with FTP servers. 
lftp mirror local directory to remote ftp server without deleting remote files which are missing locally
backup;lftp