--prune=<date>::
Prune loose objects older than date (default is 2 weeks ago,
overridable by the config variable `gc.pruneExpire`).
- --prune=all prunes loose objects regardless of their age and
+ --prune=now prunes loose objects regardless of their age and
increases the risk of corruption if another process is writing to
the repository concurrently; see "NOTES" below. --prune is on by
default.