Comment (by Roland Haas):

The simpler version is here: https://bitbucket.org/cactuscode/cactus/pull-requests/93 with it one checkout git will generate a string like $Id: 57702847595f9879e6d743a66c483770450e3e53 $ wherever $Id$ was found. Before committing / computing diffs it filters out the bits between $Id: and $ so that the file is not constantly changed (this is the same behaviour as svn).

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Ticket URL: https://bitbucket.org/einsteintoolkit/tickets/issues/2330/include-date-of-build-and-git-hash-in