From rclone.org:

Rclone is a command line program to sync files and directories to and from

• Google Drive
• Amazon S3
• Openstack Swift / Rackspace cloud files / Memset Memstore
• Dropbox
• Google Cloud Storage
• Amazon Cloud Drive
• Microsoft One Drive
• Hubic
• Backblaze B2
• Yandex Disk
• The local filesystem

Docker

Show help message:

/usr/bin/docker run --rm \
    kevineye/rclone \
    rclone --help

Interactive configuration:

touch rclone.conf
/usr/bin/docker run --rm -it \
    -v "$PWD"/rclone.conf:/root/.rclone.conf \
    kevineye/rclone \
    rclone config

Example Dropbox sync:

/usr/bin/docker run --rm \
    -v "$PWD"/rclone.conf:/root/.rclone.conf \
    -v /path/to/Dropbox:/data \
    kevineye/rclone \
    rclone sync dropbox:/ /data