TL;DR: I have a small internal hard drive and a 2TB iCloud Drive. I want to have access to all my files (iCloud), but I don't want all of my files on my computer.
In macOS (since Sierra I believe) Apple included a features where you can have your Desktop and Documents folders synced to in iCloud Drive, and if you enable it, when your drive fills up, macOS removes local copies of those files and replace it with a little placeholder.
I'm wonder if there is a way to pick and choose what files get offloaded to iCloud this way and when. Let's say I just added a file to my Documents folder that I want to keep, but I have no intention to use it for a while, so I just want it to sync to iCloud then replace the local copy with the placeholder, instead of waiting for my drive to fill up and then have macOS auto offload files for me.
Also, it would be nice to have more than just Documents and Desktop offloadable, but I'm guessing Apple doesn't expose that much functionality in their SDK that I could write an app to do that.
I currently don't develop in any Apple approved languages (Swift & Obj-C) but if there is a way to create an app with this ability to offload files to iCloud Drive I'll deep dive into the language to scratch this itch.
Note: I know I can store any file I want in iCloud Drive by dragging a file into the iCloud Drive icon in the Finder, but to my understanding, these files require a local cache of the file and not this placeholder method that Documents and Desktop folder syncing uses. If there is a way to offload through the customer facing iCloud Drive access in the Finder I'm open to that method too.
Within macOS Catalina this can now be done by right clicking the file/folder and clicking "Remove Download"