Cross-session sync broken on macOS — stat -c is Linux-only

[numarulunu]

Running into a hard failure on macOS Sonoma 14.2 when the sync script tries to check file modification times.

The error is:

stat: illegal option -- c
usage: stat [-FLnq] [-f format | -l | -r | -s | -x] [-t timefmt] [file ...]

The issue is that stat -c '%Y' is a GNU coreutils thing. macOS ships with BSD stat, which uses stat -f '%m' for the same thing.

Quick fix would be something like:

if [[ "$OSTYPE" == "darwin"* ]]; then
    mod_time=$(stat -f '%m' "$file")
else
    mod_time=$(stat -c '%Y' "$file")
fi

Or just use date -r which works on both, though it's slower for batch operations.

I can submit a PR if you want — just wanted to flag it first since it completely blocks macOS usage right now.