walking commits starting at the commits specified in stdin as a list
of OIDs in hex, one OID per line. (Cannot be combined with
--stdin-packs.)
++
+With the `--append` option, include all commits that are present in the
+existing commit-graph file.
'read'::
$ git show-ref -s | git commit-graph write --stdin-commits
------------------------------------------------
+* Write a graph file containing all commits in the current
+* commit-graph file along with those reachable from HEAD.
++
+------------------------------------------------
+$ git rev-parse HEAD | git commit-graph write --stdin-commits --append
+------------------------------------------------
+
* Read basic information from the commit-graph file.
+
------------------------------------------------