What is the best way to delete the files that were backed up via a Linux machine via the online backup software. I can connect via a Windows machine's Online Backup and change the Prefix to be that of the linux machine and supposedly should be able to delete the files. But can this be done via a command on the linux system?
If you don't need that backup from that machine any longer because it has been decommissioned, you can simply delete it from the cloud storage. Just look for the prefix for that particular machine in your cloud storage and you can delete it from the cloud storage management interface provided by the cloud storage provider.
But if you're only deleting some of the data then the best way to do it is from the storage tab in the UI on the Linux machine itself.