gem install git-amend

gem build git-amend.gemspec
gem install --local git-amend-<version>.gem
cd <repository>
git-amend

Usage: git-amend [options]
    -p, --path=<path>                Path to the target respository
    -a, --author=<email>             Author email for all commits
    -n, --author-name=<name>         Author name for all commits
    -c, --committer=<email>          Committer email for all commits
    -m, --committer-name=<name>      Committer name for all commits
    -C, --commit-hash=<hash>         The hash of git commit that needs to be updated
    -s, --shuffle                    Whether to shuffle the commit date (default: no)
    -f, --from=<date>                Date of the first commit (YYYY-mm-dd), only used with --shuffle
    -t, --to=<date>                  Date of the latest commit (YYYY-mm-dd), only used with --shuffle
    -v, --verbose                    Verbose mode
    -V, --version                    Print version
    -d, --dry-run                    Dry run without executing the actual command.