read the message from the standard input.
--author=<author>::
- Override the author name used in the commit. Use
- `A U Thor <author@example.com>` format.
+ Override the author name used in the commit. You can use the
+ standard `A U Thor <author@example.com>` format. Otherwise,
+ an existing commit that matches the given string and its author
+ name is used.
-m <msg>::
--message=<msg>::