GIT: change commit date to author date
Short Answer:
git filter-branch --env-filter 'export GIT_COMMITTER_DATE="$GIT_AUTHOR_DATE"'
Explanation:
filter-branch lets you rewrite your git history. It can apply transformations to each commit or filter out commits based on certain criteria. See git filter-branch --help for a comprehensive description and usage instructions.
--env-filter allows you to set the environment variables that are present during the creation of the new history. It is evaluated for each commit separately.