Changes an author on all commits using a bad/old email address

Git change author

# WARNING: rewrites all commits (different SHAs)


$ git filter-branch -f --env-filter '
WRONG_EMAIL="bad@email.com"
NEW_NAME="username"
NEW_EMAIL="good@email.com"

if [ "$GIT_COMMITTER_EMAIL" = "$WRONG_EMAIL" ]
then
    export GIT_COMMITTER_NAME="$NEW_NAME"
    export GIT_COMMITTER_EMAIL="$NEW_EMAIL"
fi
if [ "$GIT_AUTHOR_EMAIL" = "$WRONG_EMAIL" ]
then
    export GIT_AUTHOR_NAME="$NEW_NAME"
    export GIT_AUTHOR_EMAIL="$NEW_EMAIL"
fi
' --tag-name-filter cat -- --branches --tags

-f => force overwrite an existing backup (not needed when using only once)