How can I get the correct user in a mail filter in CVS loginfo?

I have a single CVS user (cvs) on my Unix box and I map all CVS users to this user via CVSROOT/passwd. When I do this, all mails are sent by the user cvs. I'd like to show the 开发者_JAVA技巧name of the committer in the mail subject (or even as the sender of the mail).

Is there any other way than creating a real Unix user?

CVS will put the commit user name into the variable $USER which you can use in the file loginfo to call your mail filter.