Using a Linux PC as the FROM (source) for syncs to a phone.
See also x-3-devices-with-pc-as-phone/ for using a PC as TO.

This demo's PC-side scripts were run on Linux.  It mixes 
app-specific storage for zips and shared storage for content
on the phone.


SYMLINKS

Symlinks yield perpetual diffs on Linux, because the platform
does not try to save them on exFAT proxy drives (and probably 
should not: macOS's forgery works only on macOS).  See the 
runs/* files' notes for more details, and trace the effect in
the logs/.  Symlinks would fail to be recorded correctly on 
Android shared storage too, but they never get that far.  The
upside is that they are effectively ignored on phones in this 
use case.  Using a more Linux-friendly filesystem on the proxy 
may support symlinks, but only up to the point where they would
fail on Android shared storage (app storage may fare better).
Symlinks are not generally portable across drives and platforms.


NONPORTABLE FILENAMES

The Linux test uses the unfixed zip to create test data, and 
fixes names in the initial-copy script before propagating.

The x* folder shows what happens to nonportable filenames
on Linux with an exFAT proxy if the fixer script isn't run.
The main runs fix names as a first step.