------------------------------------------------
* Write a graph file, extending the current graph file using commits
-* in <pack-index>.
+ in <pack-index>.
+
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$ echo <pack-index> | git commit-graph write --stdin-packs
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* Write a graph file containing all commits in the current
-* commit-graph file along with those reachable from HEAD.
+ commit-graph file along with those reachable from HEAD.
+
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$ git rev-parse HEAD | git commit-graph write --stdin-commits --append