git-get-tar-commit-id - Extract commit ID from an archive created using
Read a tar archive created by git archive from the standard input and
extract the commit ID stored in it. It reads only the first 1024 bytes of
input, thus its runtime is not influenced by the size of the tar archive very
If no commit ID is found, git get-tar-commit-id quietly
exists with a return code of 1. This can happen if the archive had not been
created using git archive or if the first parameter of git
archive had been a tree ID instead of a commit ID or tag.