[yes_but_no]

When apps use text based single file as data source are they flushing the whole file when user makes an update?

If I add or move a line does Bike rewrites the whole file and updates the in-mem sorted-dict op mentioned?

[jessegrosjean]

For saving to disk yes, but not on every keystroke. An autosave is scheduled and then the save is performed after some period of time. The underlying scheduling and behavior is provided by macOS framework code.

If you add a line then rows after it in the array get shifted.