rclone is a command line program to sync files and directories to and from a vast variety of cloud provider and protocols. At the time of writing, this includes the following services:
- Amazon S3 / Dreamhost / Ceph / Minio / Wasabi
- Backblaze B2
- Box
- Dropbox
- FTP
- Google Cloud Storage
- Google Drive
- HTTP
- Hubic
- Jottacloud
- Mega
- Microsoft Azure Blob Storage
- Microsoft OneDrive
- OpenDrive
- Openstack Swift / Rackspace cloud files / Memset Memstore / OVH / Oracle Cloud Storage
- pCloud
- QingStor
- SFTP
- Webdav / Owncloud / Nextcloud
- Yandex Disk
- The local filesystem
That list is regularly expanding. git-annex supports all of those through the use of the rclone special remote.
See their documentation for more concrete examples.