问题
How do I enable ident $Id$ on files in a Git repository?
回答1:
Summary: The recommended way of embedding version information in a product is to use the build system for that; see below for details and alternate approaches.
In Git (and I think usually also in other VCS systems with atomic commits) there is no such thing like version of a single file.
Git does support on-demand expansion of $Id:$ keyword, but:
- It is done on request only. You have to specify (perhaps using globbing pattern) that a file (or a set of files) has an
identattribute set (in '.gitattributes' file in tree, or in '.git/info/attributes' for local repository settings). - It expands to the SHA-1 of file contents (or to be more exact to
$Id:<sha-1 of blob>$). The reason for this choice is that Git does not touch files that have not changed during branch switching or rewinding; if '$Id:$' expanded to revision info it would require to update every version-controlled file e.g. when switching branches.
Git supports quite a wide set of $Format:...$ placeholders which expands to commit information (e.g. $Format:%H$ replaced by a commit hash) but:
- Expansion is done only when running git archive, in its output file.
- It is done on request, controlled via
export-substattribute.
The recommended way of embedding version information is to do it via the build system (in a build stage); see for example Git Makefile and GIT-VERSION-GEN script used by Makefile in the Git web interface for the git.git repository.
You can however (ab)use a clean/smudge filter driver (via filter attribute) to get CVS-like keyword expansion, expanding keywords on checkout, and cleaning them up on entering contents to the repository.
回答2:
You can do this by adding a pattern for which files you want this functionality followed by ident in the .gitattributes file. This will replace $Id$ with $Id:<40-digit SHA>$ on checkout of the file. Notice though that it won't give you a revision number of the file as in CVS/SVN.
Example:
$ echo '*.txt ident' >> .gitattributes
$ echo '$Id$' > test.txt
$ git commit -a -m "test"
$ rm test.txt
$ git checkout -- test.txt
$ cat test.txt
Link to gitattributes(5) Manual Page
回答3:
Git's ident does not do what $Id$ does in other versioning systems. As a kludge, use RCS along with git: RCS for individual file revisions and git to checkpoint the project as a whole. As I said, this is a kludge but it does kinda make sense (sometimes for some things).
来源：https://stackoverflow.com/questions/1792838/how-do-i-enable-the-ident-string-for-a-git-repository