[git] GIT commit as different user without email / or only email

Format

A U Thor <[email protected]>

simply mean that you should specify

FirstName MiddleName LastName <[email protected]>

Looks like middle and last names are optional (maybe the part before email doesn't have a strict format at all). Try, for example, this:

git commit --author="John <[email protected]>" -m "some fix"

As the docs say:

  --author=<author>
       Override the commit author. Specify an explicit author using the standard 
       A U Thor <[email protected]> format. Otherwise <author> is assumed to 
       be a pattern and is used to search for an existing commit by that author 
       (i.e. rev-list --all -i --author=<author>); the commit author is then copied 
       from the first such commit found.

if you don't use this format, git treats provided string as a pattern and tries to find matching name among the authors of other commits.