When I've needed to do simple stuff with this is the past, I just manipulate mailmain by send email from Zope to mailman's admin interface...
Pipes seem easier to me. Responses from the command line scripts seem much easier to use for confirmation. And there are things you can do easily from the cli interface that you either can't do through email, are difficult to do through email, or possibly I just don't know how to do through email.
And yeah, tempfile would work, although, I have to admit I really don't see the point of it when you are only storing one file. I am probably missing some usecase or good programming practice here, but it seems like it saves you a single line for the delete in return for an extra module import.
What happens when two users do something that creates one of these temp files at exactly the same time? ;-)
Yah, you and Tres Seaver (OL) both made this point, and thanks for saving me from having much wailing and gnashing of teeth over my dimness once this actually went live. Thanks for the help, J.P. Withers