So I recently quitted Google Drive and downloaded all my data and hoping to keep it on Hard drives myself, They are external plug in types and I want the files synced like it was on my computer. So when I plug it in it copies/syncs the things on my computer, anyone knows somethign like that?
Rsync.
You could leave the drive plugged in and schedule a daily/hourly sync, or you could have the system trigger a sync whenever you plug the drive in.