repository script in https://github.com/WindomZ/gitdate

gitdate

rm -rf "$(git rev-parse --git-dir)/refs/original/" && \
git filter-branch --env-filter \
"if [ \$GIT_COMMIT = \"$(git rev-parse HEAD)\" ]; then
    export GIT_AUTHOR_DATE=\"$1\"
    export GIT_COMMITTER_DATE=\"$1\"
    export GIT_COMMITTER_NAME=\$GIT_AUTHOR_NAME
    export GIT_COMMITTER_EMAIL=\$GIT_AUTHOR_EMAIL
fi"