This issue is really minor but I'll mention it anyway: Is there a reason why sortm exits with a nonzero status when asked to sort a folder with no messages? To me it seems more natural for that case to be handled as a boundary but nonerror case and exit with a normal (zero) status. It seems weird to treat sorting an empty list as an error. For instance, the 'sort' program doesn't indicate an abnormal termination in such cases.
The pragmatic reason for this question/request is that when sortm is called by other programs it can result in unnecessary error/warning notifications (such as in emacs, via mh-e, the nonzero exit status leads to a benign but distracting error message). Looking at the source code, the behavior seems easy enough to change but I suspect there may be historical or other reasons that I'm overlooking. Regards, -chaw
