Git: reset author for ALL commits

git-reset-author.sh

#!/bin/sh

# Credits: http://stackoverflow.com/a/750191

git filter-branch -f --env-filter "
    GIT_AUTHOR_NAME='Newname'
    GIT_AUTHOR_EMAIL='new@email'
    GIT_COMMITTER_NAME='Newname'
    GIT_COMMITTER_EMAIL='new@email'
  " HEAD

@biniama

git filter-repo solution:

git filter-repo --preserve-commit-hashes --name-callback "$(cat <<'EOF'
return b'<replace everything between the quotes with your name>'
EOF
)" --email-callback "$(cat <<'EOF'
return b'<replace everything between the quotes with your email>'
EOF
)"

If you had signed your commits before this, note that the above command will remove those signatures. For me, this answer was useful to resign all commits without loosing commit dates.