With the --stdin-packs option, generate the new commit graph by walking objects only in the specified pack-indexes. (Cannot be combined with --stdin-commits.)

       With the --stdin-commits option, generate the new commit graph by 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
       Read a graph file given by the commit-graph file and output basic details about the graph file. Used for debugging purposes.

           $ git commit-graph write

   ·   Write a graph file, extending the current graph file using commits

   ·   in <pack-index>.

           $ echo <pack-index> | git commit-graph write --stdin-packs

   ·   Write a graph file containing all reachable commits.

           $ 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.

           $ git commit-graph read